diff --git a/src/main/java/fr/inria/corese/core/next/impl/common/util/IRIUtils.java b/src/main/java/fr/inria/corese/core/next/impl/common/util/IRIUtils.java
index bb1f83146..7c4a819b3 100644
--- a/src/main/java/fr/inria/corese/core/next/impl/common/util/IRIUtils.java
+++ b/src/main/java/fr/inria/corese/core/next/impl/common/util/IRIUtils.java
@@ -10,9 +10,10 @@
  */
 public class IRIUtils {
 
-    private static final Pattern IRI_PATTERN = Pattern.compile("^(([\\w\\-]+:\\/\\/([\\w\\-_:]+\\.)*[\\w\\-_:]*)(\\/([\\w\\-\\._\\:]+\\/)*))([\\w\\-\\._\\:]+)?(\\?[\\w\\-_\\:\\?\\=]+)?((\\#)?([\\w\\-_]+))?$");
+    private static final Pattern IRI_PATTERN = Pattern.compile("^(?<namespace>(?<protocol>[\\w\\-]+):(?<dblSlashes>\\/\\/)?(?<domain>([\\w\\-_:@]+\\.)*[\\w\\-_:]*))((?<path>\\/([\\w\\-\\._\\:]+\\/)*)(?<finalPath>[\\w\\-\\._\\:]+)?(?<query>\\?[\\w\\-_\\:\\?\\=]+)?(\\#)?(?<fragment>([\\w\\-_]+))?)?$");
     private static final Pattern STANDARD_IRI_PATTERN = Pattern.compile("^(([^:/?#\\s]+):)(\\/\\/([^/?#\\s]*))?([^?#\\s]*)(\\?([^#\\s]*))?(#(.*))?");
 
+
     /**
      * Prevent instantiation of the utility class.
      */
@@ -29,15 +30,24 @@ public static String guessNamespace(String iri) {
             Matcher matcher = IRI_PATTERN.matcher(iri);
 
             if(matcher.matches()) {
-                if((matcher.group(8) == null) || (matcher.group(6) == null && matcher.group(9) == null) ) { // If the IRI has no fragment or ends with a slash
-
-                    return matcher.group(1);
-                } else {
-                    // 1: Domain and path ending with a slash, 6: final path element without slash, 9: final # if there is a fragment
-                    return matcher.group(1) + matcher.group(6) + matcher.group(9);
+                if(matcher.group("protocol") != null && matcher.group("protocol").equals("_")) {
+                    return "";
+                }
+                StringBuilder namespace = new StringBuilder();
+                namespace.append(matcher.group("protocol")).append(":");
+                if(matcher.group("dblSlashes") != null) {
+                    namespace.append(matcher.group("dblSlashes"));
                 }
+                namespace.append(matcher.group("domain"));
+                if(matcher.group("path") != null) {
+                    namespace.append(matcher.group("path"));
+                }
+                if(matcher.group("fragment") != null && matcher.group("finalPath") != null) {
+                    namespace.append(matcher.group("finalPath")).append("#");
+                }
+                return namespace.toString();
             } else {
-                return "";
+                throw new IllegalStateException("No namespace found for the given IRI: " + iri + ".");
             }
         } catch (IllegalStateException e) {
             return "";
@@ -54,10 +64,10 @@ public static String guessLocalName(String iri) {
             Matcher matcher = IRI_PATTERN.matcher(iri);
 
             if(matcher.matches()) {
-                if(matcher.group(10) != null){ // If the IRI has a fragment
-                    return matcher.group(10);
-                } else if(matcher.group(6) != null ) { // If the IRI has no fragment but do not ends with a slash
-                    return matcher.group(6);
+                if(matcher.group("fragment") != null){ // If the IRI has a fragment
+                    return matcher.group("fragment");
+                } else if(matcher.group("finalPath") != null ) { // If the IRI has no fragment but do not ends with a slash
+                    return matcher.group("finalPath");
                 } else { // If the URI ends with a slash
                     return "";
                 }
diff --git a/src/test/java/fr/inria/corese/core/next/impl/temp/CoreseIRITest.java b/src/test/java/fr/inria/corese/core/next/impl/temp/CoreseIRITest.java
index 9519cd4f0..77bfc928c 100644
--- a/src/test/java/fr/inria/corese/core/next/impl/temp/CoreseIRITest.java
+++ b/src/test/java/fr/inria/corese/core/next/impl/temp/CoreseIRITest.java
@@ -30,6 +30,21 @@ public void constructorStringTest() {
         assertEquals("test", coreseIRI.getLocalName());
     }
 
+    @Test
+    public void constructorStringTest_otherURIS() {
+        CoreseIRI coreseIRI_noSlash = new CoreseIRI("http://www.monicamurphy.org");
+        assertEquals("http://www.monicamurphy.org", coreseIRI_noSlash.stringValue());
+        assertEquals("http://www.monicamurphy.org", coreseIRI_noSlash.getCoreseNode().getLabel());
+        assertEquals("http://www.monicamurphy.org", coreseIRI_noSlash.getNamespace());
+        assertEquals("", coreseIRI_noSlash.getLocalName());
+
+        CoreseIRI coreseIRI_email = new CoreseIRI("mailto:monica@monicamurphy.org");
+        assertEquals("mailto:monica@monicamurphy.org", coreseIRI_email.stringValue());
+        assertEquals("mailto:monica@monicamurphy.org", coreseIRI_email.getCoreseNode().getLabel());
+        assertEquals("mailto:monica@monicamurphy.org", coreseIRI_email.getNamespace());
+        assertEquals("", coreseIRI_email.getLocalName());
+    }
+
     @Test
     public void constructorIriTest() {
         CoreseIRI coreseIRI = new CoreseIRI("http://example.org/test");