BRUSSELS (AP) -- Belgian security forces killed two terror suspects in a fierce shootout in the eastern city of Verviers on Thursday and arrested another, foiling a major attack against police buildings, authorities said.

The suspects immediately opened fire on police when they closed in on them near the city's train station, Magistrate Eric Van der Sypt said in Brussels. He said there was no link at this stage to the Paris attacks, and that the raid is the result of an investigation that has been underway for a few weeks.

"These were extremely well-armed men," with automatic weapons, Van der Sypt said. Police buildings were the target, and an attack had been expected in hours or days, he said.

There was an intense firefight for several minutes on an upper level of a building in Verviers where the raid took place. The building where the raid took place is multistory and appears to be residential.

"We still expect a number of arrests," he said. No police were wounded or killed in the firefight, which occurred at the height of rush hour in a crowded neighborhood.

The magistrate said more anti-terrorist raids were underway in the Brussels region and Verviers, adding that Belgium's terror alert level was raised to its second-highest level. The operation was part of an investigation into extremists returning from Syria, authorities said.

Verviers is a former industrial town with a large immigrant population about 125 kilometers (80 miles) southeast of the capital, Brussels.

Witnesses speaking on Belgium's RTBF radio described a series of explosions followed by rapid fire at the center of Verviers, near a bakery and in the neighborhood of the train station. Video posted online of what appeared to be the raid showed a dark view of a building amid blasts, gunshots and sirens, and a fire with smoke billowing up.

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