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, where Sen. Ronald dela Rosa has stayed in protective custody by allied senators as Philippine authorities tried to arrest him and possibly turn him over later to the ICC.