Police in Turkey arrested two gunmen near the entrance to Istanbul’s Dolmabahce Palace on Wednesday, according to Turkey’s Dogan News Agency.
The arrests came after gunfire was reported near a police station at the entrance to the palace.
No injuries or deaths were immediately reported. The two suspects were carrying automatic weapons.
The incident comes after the United States began launching manned airstrikes against ISIS from a base in Turkey for the first time last week.
The United States has long wanted to use Turkish bases for manned airstrikes against ISIS in Syria and parts of Iraq. Such access should shorten flight times for U.S. (and presumably allied) fighter jets — especially into Syria, where the group calling itself the Islamic State has its de facto capital in Raqqa — compared with taking off from bases in Iraq or aircraft carriers in the Persian Gulf.
Turkey has long endured the buildup of ISIS on its long and porous border with Syria, but until July was reluctant to permit the U.S. to use its bases to strike the radical militant group.
Ankara has been under long and consistent pressure from allies to move more directly against ISIS. The pressure increased inside Turkey after a series of attacks blamed on the group.
In July, a suicide blast that authorities blame on ISIS killed 32 people in Suruc, Turkey. Also that month, Turkey said ISIS militants attacked Turkish troops at the Turkey-Syria border, killing a soldier.