Turkey's prime minister crossed into Syrian territory in an armored convoy Sunday to pay a surprise visit to the tomb of the grandfather of the founder of the Ottoman Empire, ABC News reported.

The move prompted immediate criticism from Syria, which accused Turkey of acting aggressively toward a sovereign state.

In February, Turkey sent hundreds of troops into Syria to move the tomb — which was being besieged by Islamic State militants — closer to the Turkish border and to evacuate dozens of Turkish soldiers who were guarding it.

It was the first major military incursion into Syria by Turkey since the Syrian conflict began in March 2011.

Turkish Prime Minister Ahmet Davutoglu visited the shrine — which now lies 250 meters (yards) from the Turkish border in Syria's Ashma region — while on the campaign trail Sunday ahead of Turkey's June 7 general election.

The private Dogan news agency said he crossed into Syria in a convoy of armored vehicles protected by helicopters.

Syria's state news agency SANA called Davutoglu's visit to Syria without the approval of the Syrian government "a clear aggression on a sovereign state ... and a violation of all laws and charters."