Istanbul - (AFP) - Ankara on Saturday warned its citizens against traveling to the United States and Europe, apparently in response to similar warnings against travel to Turkey .

The United States and major European countries have advised their citizens not to attend mass events and to avoid crowded tourist places in Turkey.

These warnings came against the backdrop of escalating diplomatic tensions related to Turkey's refusal to allow Sweden and Finland to join the North Atlantic Treaty Organization (NATO).

Ankara recently expressed its anger at anti-Islam protests organized by a right-wing extremist who was allowed to burn copies of the Koran in front of its embassies in Stockholm and Copenhagen.

The Turkish Foreign Ministry warned of "dangerous levels of religious intolerance and hatred in Europe".

"There have been recent verbal and physical attacks against aliens and acts of racism across the United States," it said in a separate statement.

Finland and Sweden broke decades of military non-alignment and applied to join NATO in response to Russia's invasion of Ukraine.

But an application for membership must be approved by all thirty members of the alliance.

Turkey and Hungary are the only two countries that have not yet ratified the two applications.

The Hungarian Parliament is expected to ratify the two requests next month.

But Turkish President Recep Tayyip Erdogan still refuses to accept the two requests, accusing the two countries of harboring Kurdish activists and sympathizers of the PKK and its allies in northern Syria and Iraq, whom it describes as "terrorists".