Heavy gunfire erupted on Monday in Ivory Coast’s two largest cities – Abidjan and Bouake – witnesses said, as the military pressed an operation aimed at ending a four-day nationwide army mutiny over bonus payments.

Loyalist troops began advancing towards Bouake, the epicentre of the revolt, on Sunday and sporadic gunfire was heard overnight there as well as at military camps in Abidjan. Shooting in both cities intensified before dawn.

Heavy shooting was also heard in Daloa, a hub for the western cocoa growing regions, on Monday.

“I’ve been hearing the sound of Kalashnikovs and a heavier weapon. That began at around 5 a.m. (0500 GMT) … It’s intense,” said one Abidjan resident, who lives near the U.S. Embassy and the presidential residence.

Another Abidjan resident said mutinying soldiers came out of the country’s largest military camp and erected barricades, blocking traffic along one of the main thoroughfares in the east of the city.

“There was heavy shooting at the northern entrance to the city and in the city centre. It’s calmed a bit but we’re still hearing gunfire,” said one Bouake resident. A second resident confirmed the shooting.

Meanwhile, Ivory Coast’s banking association, the APBEF, ordered all banks to remain closed on Monday.

“There was an emergency meeting this morning and the APBEF took the decision that, for security reasons, all the banks would stay closed,” a senior official with Banque Atlantique, who asked not to be named, told Reuters.