MARAWI, Philippines (AP) — The Latest on the siege of a southern Philippine city by militants linked to the Islamic State group (all times local):

4:15 p.m.

A military spokesman says troops are using helicopters to help clear militants from the besieged city of Marawi in the southern Philippines.

Lt. Col. Jo-ar Herrera says the helicopters are firing rockets in "a precision attack."

As gunfire crackled in the background, Herrera says authorities believe Isnilon Hapilon, who is on Washington's list of most-wanted terrorists, is still in the city.

The violence erupted Tuesday night when authorities launched an unsuccessful raid to capture Hapilon.

1 p.m.

Catholics in the Philippine capital have attended a Mass for people in the southern region now under martial law and in Marawi.

The city of about 200,000 people was under attack by Muslim militants and people were packing into vehicles to flee the violence Thursday as army trucks rolled into the city center. The Philippines is Asia's largest Roman Catholic nation, but its southern region has a large Muslim minority.

At the Mass in Manila, nun Mary John Mananzan called on people to pray and noted that hostages had been taken, including a priest from the cathedral in Marawi.

People were also protesting out of concern the martial law was too broadly applied. Protest leader Teddy Casino warned that there might be more extrajudicial killings and human rights violations.

12:30 p.m.

Army tanks packed with soldiers have rolled into a southern Philippine city to try to restore control after militants linked to Islamic State group launched a violent siege.

Thousands of civilians have been fleeing the city of some 200,000 people.

At least 21 people have died in fighting that erupted late Tuesday, when the army raided the Marawi hideout of Isnilon Hapilon. Hapilon is on Washington's list of most-wanted terrorists and has a $5 million bounty on his head.

But the operation quickly went wrong as the militants called in reinforcements. The city of Marawi was still largely sealed off Thursday, although automatic gunfire and explosions could be heard. Plumes of black smoke rose from the direction of the city center and air force helicopters swooped overhead.