CAIRO (AP) -- Fire swept the upper floors of Egypt's Interior Ministry building on Tuesday as policemen protested outside to demand higher pay. A security official accused demonstrators of starting the blaze in downtown Cairo.

TV footage showed flames climbing the top floors of the building and a huge plume of black smoke filling the sky. Later, firefighters on tall ladders sprayed water to extinguish the fire. The Skanner News Video: Egypt and Democracy

One protester denied they had lit the fire and accused those inside of setting if off by burning security files to get rid of evidence of police abuses.

Many Egyptians still associate the Interior Ministry's security forces with the worst excesses of the regime of ousted President Hosni Mubarak. Earlier this month, protesters rallied outside State Security offices across the nation, storming some of them in a search of evidence of human rights violations.

Tuesday's protest outside the ministry, however, was held by policemen themselves. They want a minimum salary of $200 a month - much more than many get now - and other benefits, including improved health care. The mass demonstrations that toppled Mubarak on Feb. 11 have set off frequent protests by laborers, including police officers, seeking to improve their lot.

The security official said protesters lit the fire in the building housing in the ministry's personnel department. It then spread to an adjacent communications building.

One protester who arrived to see fires burning in the two buildings said it couldn't have been started by the crowd because they had no way of entering the heavily guarded compound. He accused workers inside of burning security files and starting the blaze.

"It is as if light just started to arrive and they want to bring back the darkness," he said, giving only his first name, Amil, because he feared government retribution.

About 15 central security trucks cordoned off the complex to prevent demonstrators from storming it. It remained unclear how the fire started, though onlookers said it appeared to begin in the six-story building's middle floors, then spread to the top.

Thousands of people collected in nearby streets to watch as four fire trucks extinguished the blaze. Military police in khaki uniforms and red berets prevented them from approaching the building.

Tuesday's demonstration also called for the return of former Interior Minister Mahmoud Wagdi, whom Egypt's military rulers replaced in a Cabinet shake-up this month aimed at removing stalwarts of the Mubarak regime.

Wagdi, who held the post for less than a month, was replaced by Maj. Gen. Mansour el-Essawy, a former Cairo security chief who has pledged to restore security and reduce the role of the hated State Security agency.