diff --git a/src/main/java/fr/inria/corese/core/next/data/impl/io/parser/nquads/NQuadsParser.java b/src/main/java/fr/inria/corese/core/next/data/impl/io/parser/nquads/NQuadsParser.java
index c112f69e8..fb9f321d2 100644
--- a/src/main/java/fr/inria/corese/core/next/data/impl/io/parser/nquads/NQuadsParser.java
+++ b/src/main/java/fr/inria/corese/core/next/data/impl/io/parser/nquads/NQuadsParser.java
@@ -16,8 +16,6 @@
 import java.io.InputStream;
 import java.io.InputStreamReader;
 import java.io.Reader;
-import java.net.URI;
-import java.net.URISyntaxException;
 import java.nio.charset.CodingErrorAction;
 import java.nio.charset.StandardCharsets;
 import java.util.HashMap;
@@ -203,14 +201,34 @@ private static boolean forbiddenIriCharacter(int c) {
         }
 
         private void validateIri(String text) {
-            try {
-                URI uri = new URI(text);
-                if (!uri.isAbsolute()) {
-                    throw error("N-Quads requires an absolute IRI");
+            if (!isAbsoluteIri(text)) {
+                throw error("N-Quads requires an absolute IRI");
+            }
+        }
+
+        private static boolean isAbsoluteIri(String text) {
+            if (text == null || text.isEmpty() || !isAsciiAlpha(text.charAt(0))) {
+                return false;
+            }
+            int i = 1;
+            int length = text.length();
+            while (i < length) {
+                char c = text.charAt(i);
+                if (isSchemeChar(c)) {
+                    i++;
+                } else {
+                    break;
                 }
-            } catch (URISyntaxException e) {
-                throw new ParsingException(location("Invalid absolute IRI: " + e.getReason()), e);
             }
+            return i < length && text.charAt(i) == ':';
+        }
+
+        private static boolean isAsciiAlpha(char c) {
+            return (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z');
+        }
+
+        private static boolean isSchemeChar(char c) {
+            return isAsciiAlpha(c) || (c >= '0' && c <= '9') || c == '+' || c == '-' || c == '.';
         }
 
         private BNode blankNode() throws IOException {
diff --git a/src/main/java/fr/inria/corese/core/next/data/impl/io/parser/ntriples/NTriplesParser.java b/src/main/java/fr/inria/corese/core/next/data/impl/io/parser/ntriples/NTriplesParser.java
index cc0ae3a16..174819313 100644
--- a/src/main/java/fr/inria/corese/core/next/data/impl/io/parser/ntriples/NTriplesParser.java
+++ b/src/main/java/fr/inria/corese/core/next/data/impl/io/parser/ntriples/NTriplesParser.java
@@ -16,8 +16,6 @@
 import java.io.InputStream;
 import java.io.InputStreamReader;
 import java.io.Reader;
-import java.net.URI;
-import java.net.URISyntaxException;
 import java.nio.charset.CodingErrorAction;
 import java.nio.charset.StandardCharsets;
 import java.util.HashMap;
@@ -182,14 +180,34 @@ private static boolean forbiddenIriCharacter(int c) {
         }
 
         private void validateIri(String text) {
-            try {
-                URI uri = new URI(text);
-                if (!uri.isAbsolute()) {
-                    throw error("N-Triples requires an absolute IRI");
+            if (!isAbsoluteIri(text)) {
+                throw error("N-Triples requires an absolute IRI");
+            }
+        }
+
+        private static boolean isAbsoluteIri(String text) {
+            if (text == null || text.isEmpty() || !isAsciiAlpha(text.charAt(0))) {
+                return false;
+            }
+            int i = 1;
+            int length = text.length();
+            while (i < length) {
+                char c = text.charAt(i);
+                if (isSchemeChar(c)) {
+                    i++;
+                } else {
+                    break;
                 }
-            } catch (URISyntaxException e) {
-                throw new ParsingException(location("Invalid absolute IRI: " + e.getReason()), e);
             }
+            return i < length && text.charAt(i) == ':';
+        }
+
+        private static boolean isAsciiAlpha(char c) {
+            return (c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z');
+        }
+
+        private static boolean isSchemeChar(char c) {
+            return isAsciiAlpha(c) || (c >= '0' && c <= '9') || c == '+' || c == '-' || c == '.';
         }
 
         private BNode blankNode() throws IOException {
diff --git a/src/test/java/fr/inria/corese/core/next/data/impl/io/parser/nquads/NQuadsParserTest.java b/src/test/java/fr/inria/corese/core/next/data/impl/io/parser/nquads/NQuadsParserTest.java
index 0bccbe03b..c3fa29be5 100644
--- a/src/test/java/fr/inria/corese/core/next/data/impl/io/parser/nquads/NQuadsParserTest.java
+++ b/src/test/java/fr/inria/corese/core/next/data/impl/io/parser/nquads/NQuadsParserTest.java
@@ -15,6 +15,7 @@
 import java.io.StringReader;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.mockito.Mockito.*;
 
 /**
@@ -195,4 +196,36 @@ void testParseUnicodeEscapeIRIUxInGraph() throws ParsingException {
         parser.parse(new StringReader(nquad));
         verify(mockModel).add(mockSubjectIRI, mockPredicateIRI, mockObjectIRI, expectedGraphIRI);
     }
+
+    @Test
+    @DisplayName("Test parsing a quad with non-ASCII Unicode characters in IRI (W3C test060 NBSP and math symbols)")
+    void testParseNonAsciiUnicodeInIRI() throws ParsingException {
+        String nquad = "<urn:ex:s:003> <urn:ex:020> <urn:ex:\\u00a0> <urn:ex:\\u221e> .";
+        IRI expectedSubject = mock(IRI.class);
+        IRI expectedPredicate = mock(IRI.class);
+        IRI expectedObject = mock(IRI.class);
+        IRI expectedGraph = mock(IRI.class);
+
+        lenient().when(mockValueFactory.createIRI(eq("urn:ex:s:003"))).thenReturn(expectedSubject);
+        lenient().when(mockValueFactory.createIRI(eq("urn:ex:020"))).thenReturn(expectedPredicate);
+        lenient().when(mockValueFactory.createIRI(eq("urn:ex:\u00a0"))).thenReturn(expectedObject);
+        lenient().when(mockValueFactory.createIRI(eq("urn:ex:\u221e"))).thenReturn(expectedGraph);
+
+        parser.parse(new StringReader(nquad));
+        verify(mockModel).add(expectedSubject, expectedPredicate, expectedObject, expectedGraph);
+    }
+
+    @Test
+    @DisplayName("Test parsing rejects relative IRIs in N-Quads")
+    void testParseRejectsRelativeIRI() {
+        String nquad = "<relative/iri> <http://example.org/p> <http://example.org/o> .";
+        assertThrows(ParsingException.class, () -> parser.parse(new StringReader(nquad)));
+    }
+
+    @Test
+    @DisplayName("Test parsing rejects IRIs without valid scheme")
+    void testParseRejectsInvalidScheme() {
+        String nquad = "<:invalidScheme> <http://example.org/p> <http://example.org/o> .";
+        assertThrows(ParsingException.class, () -> parser.parse(new StringReader(nquad)));
+    }
 }
diff --git a/src/test/java/fr/inria/corese/core/next/data/impl/io/parser/ntriples/NTriplesParserTest.java b/src/test/java/fr/inria/corese/core/next/data/impl/io/parser/ntriples/NTriplesParserTest.java
index 17b18aa4a..643ba2835 100644
--- a/src/test/java/fr/inria/corese/core/next/data/impl/io/parser/ntriples/NTriplesParserTest.java
+++ b/src/test/java/fr/inria/corese/core/next/data/impl/io/parser/ntriples/NTriplesParserTest.java
@@ -15,6 +15,7 @@
 import java.io.StringReader;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 import static org.mockito.Mockito.*;
 
 /**
@@ -210,4 +211,34 @@ void testParseUnicodeEscapeIRIU() throws ParsingException {
         parser.parse(new StringReader(ntriple));
         verify(mockModel).add(expectedSubjectIRI, mockPredicateIRI, mockObjectIRI);
     }
+
+    @Test
+    @DisplayName("Test parsing a triple with non-ASCII Unicode characters in IRI (W3C test060 NBSP and math symbols)")
+    void testParseNonAsciiUnicodeInIRI() throws ParsingException {
+        String ntriple = "<urn:ex:s:003> <urn:ex:020> <urn:ex:\\u00a0> .";
+        IRI expectedSubject = mock(IRI.class);
+        IRI expectedPredicate = mock(IRI.class);
+        IRI expectedObject = mock(IRI.class);
+
+        lenient().when(mockValueFactory.createIRI(eq("urn:ex:s:003"))).thenReturn(expectedSubject);
+        lenient().when(mockValueFactory.createIRI(eq("urn:ex:020"))).thenReturn(expectedPredicate);
+        lenient().when(mockValueFactory.createIRI(eq("urn:ex:\u00a0"))).thenReturn(expectedObject);
+
+        parser.parse(new StringReader(ntriple));
+        verify(mockModel).add(expectedSubject, expectedPredicate, expectedObject);
+    }
+
+    @Test
+    @DisplayName("Test parsing rejects relative IRIs in N-Triples")
+    void testParseRejectsRelativeIRI() {
+        String ntriple = "<relative/iri> <http://example.org/p> <http://example.org/o> .";
+        assertThrows(ParsingException.class, () -> parser.parse(new StringReader(ntriple)));
+    }
+
+    @Test
+    @DisplayName("Test parsing rejects IRIs without valid scheme in N-Triples")
+    void testParseRejectsInvalidScheme() {
+        String ntriple = "<:invalidScheme> <http://example.org/p> <http://example.org/o> .";
+        assertThrows(ParsingException.class, () -> parser.parse(new StringReader(ntriple)));
+    }
 }