diff --git a/src/util/util.ts b/src/util/util.ts
index 8b103e3..bbde905 100644
--- a/src/util/util.ts
+++ b/src/util/util.ts
@@ -17,11 +17,16 @@
 
 import { mustGetDefaultFileSystem } from '../persist';
 
-const escapeAssertionReg = new RegExp(/(^|[^A-Za-z0-9_])([rp])[0-9]*\./g);
+const escapeAssertionReg = new RegExp(/([()\s|&,=!><+\-*/]|^)((r|p)[0-9]*)\./g);
 
 function escapeAssertion(s: string): string {
-  s = s.replace(escapeAssertionReg, (match, p1, p2) => {
-    return p1 + p2 + match.substring(p1.length + p2.length).replace('.', '_');
+  s = s.replace(escapeAssertionReg, (match) => {
+    // Replace only the last dot with underscore (preserve the prefix character)
+    const lastDotIdx = match.lastIndexOf('.');
+    if (lastDotIdx > 0) {
+      return match.substring(0, lastDotIdx) + '_';
+    }
+    return match;
   });
   return s;
 }
diff --git a/test/enforcer.test.ts b/test/enforcer.test.ts
index 06f88d8..059e499 100644
--- a/test/enforcer.test.ts
+++ b/test/enforcer.test.ts
@@ -627,6 +627,26 @@ test('test ABAC single eval() with r. in unexpected places', async () => {
   await testEnforce(e, { id: 3 }, ({ owner: { id: 2 } } as unknown) as string, 'read', false);
 });
 
+test('test escapeAssertion with string literals (issue)', async () => {
+  // Test case from GitHub issue: escapeAssertion should not replace r./p. inside string literals
+  const MY_RESOURCE_NAME = 'r.my_resource';
+  const model = newModel();
+  model.addDef('r', 'r', 'act, obj');
+  model.addDef('p', 'p', 'act, obj, rule');
+  model.addDef('e', 'e', 'some(where (p.eft == allow))');
+  model.addDef('m', 'm', 'r.act == p.act && r.obj == p.obj && eval(p.rule)');
+
+  const enforcer = await newEnforcer(model);
+  enforcer.addPolicy('alice', MY_RESOURCE_NAME, `p.obj == "${MY_RESOURCE_NAME}"`);
+
+  // Should work because string literals are not escaped
+  await expect(enforcer.enforce('alice', MY_RESOURCE_NAME)).resolves.toBe(true);
+
+  // Test with single quotes as well
+  enforcer.addPolicy('bob', 'p.resource', `p.obj == 'p.resource'`);
+  await expect(enforcer.enforce('bob', 'p.resource')).resolves.toBe(true);
+});
+
 test('TestEnforceSync', async () => {
   const m = newModel();
   m.addDef('r', 'r', 'sub, obj, act');
diff --git a/test/util.test.ts b/test/util.test.ts
index cd9c70e..8a5c3f8 100644
--- a/test/util.test.ts
+++ b/test/util.test.ts
@@ -228,3 +228,27 @@ test('bracketCompatible', () => {
     )
   ).toEqual("g(r.sub, p.sub) && r.obj == p.obj && r.act == p.act || r.obj in ['data2', 'data3'] || r.obj in ['data4', 'data5']");
 });
+
+test('test escapeAssertion', () => {
+  expect(util.escapeAssertion('r_sub == r_obj.value')).toEqual('r_sub == r_obj.value');
+  expect(util.escapeAssertion('p_sub == r_sub.value')).toEqual('p_sub == r_sub.value');
+  expect(util.escapeAssertion('r.attr.value == p.attr')).toEqual('r_attr.value == p_attr');
+  expect(util.escapeAssertion('r.attr.value == p.attr')).toEqual('r_attr.value == p_attr');
+  expect(util.escapeAssertion('r.attp.value || p.attr')).toEqual('r_attp.value || p_attr');
+  expect(util.escapeAssertion('r2.attr.value == p2.attr')).toEqual('r2_attr.value == p2_attr');
+  expect(util.escapeAssertion('r2.attp.value || p2.attr')).toEqual('r2_attp.value || p2_attr');
+  expect(util.escapeAssertion('r.attp.value &&p.attr')).toEqual('r_attp.value &&p_attr');
+  expect(util.escapeAssertion('r.attp.value >p.attr')).toEqual('r_attp.value >p_attr');
+  expect(util.escapeAssertion('r.attp.value <p.attr')).toEqual('r_attp.value <p_attr');
+  expect(util.escapeAssertion('r.attp.value +p.attr')).toEqual('r_attp.value +p_attr');
+  expect(util.escapeAssertion('r.attp.value -p.attr')).toEqual('r_attp.value -p_attr');
+  expect(util.escapeAssertion('r.attp.value *p.attr')).toEqual('r_attp.value *p_attr');
+  expect(util.escapeAssertion('r.attp.value /p.attr')).toEqual('r_attp.value /p_attr');
+  expect(util.escapeAssertion('!r.attp.value /p.attr')).toEqual('!r_attp.value /p_attr');
+  expect(util.escapeAssertion('g(r.sub, p.sub) == p.attr')).toEqual('g(r_sub, p_sub) == p_attr');
+  expect(util.escapeAssertion('g(r.sub,p.sub) == p.attr')).toEqual('g(r_sub,p_sub) == p_attr');
+  expect(util.escapeAssertion('(r.attp.value || p.attr)p.u')).toEqual('(r_attp.value || p_attr)p_u');
+  // Test that patterns inside strings are not escaped
+  expect(util.escapeAssertion('r.sub == "a.p.p.l.e"')).toEqual('r_sub == "a.p.p.l.e"');
+  expect(util.escapeAssertion('r.sub == "test.p.value"')).toEqual('r_sub == "test.p.value"');
+});