MANILA, Philippines (AP) — A burst of gunfire rang out Wednesday night in the Philippine Senate, where authorities have tried to arrest a senator who is wanted by the International Criminal Court for a charge of crime against humanity, an Associated Press journalist and other witnesses said.

It wasn’t immediately clear what set off the gunfire or if there were injuries in the Senate chamber, where Sen. Ronald dela Rosa has stayed under the protection of allied senators as Philippine authorities tried to arrest him and possibly turn him over later to the ICC.

The ICC had no immediate comment on the events in Manila.

Senate President Alan Cayetano briefly appeared before journalists in the Senate and confirmed that he has been told by the building’s security that gunshots were fired, but he didn’t provide other details and hastily left.

“The emotions are high here,” Cayetano said. “This is the Senate of the Philippines and we are allegedly under attack.”