CAIRO-- Egyptian security forces clashed with protesters camped outside the Cabinet building Saturday, leaving one man dead, as tensions rose two days ahead of parliamentary elections being held despite mass demonstrations against military rule.

The violence occurred as a wave of protests against military rule was given extra impetus by the Egyptian military's decision on Friday to appoint a prime minister who served under deposed President Hosni Mubarak.

The Obama administration has increased pressure on Egypt's military rulers, who took over from Mubarak, to transfer power to civilian leaders throwing its support behind tens of thousands of protesters massed on Cairo's central Tahrir for more than a week.

Hundreds also had gathered outside the Cabinet building, a few blocks away, to prevent newly appointed Prime Minister Kamal el-Ganzouri from entering to take up his new post. They clashed with security forces who allegedly tried to disperse them.

An Associated Press cameraman saw three police troop carriers and an armored vehicle firing tear gas as they were being chased from the site by rock-throwing protesters.

The man who was killed was run over by one of the vehicles, but there were conflicting accounts about the circumstances surrounding the death.

The Interior Ministry expressed regret for the death of the protester, identified as Ahmed Serour, and said it was an accident.

Police didn't intend to storm the sit-in but were merely heading to the Interior Ministry headquarters, located behind the Cabinet building, when they came under attack by angry protesters throwing firebombs, it said in a statement. The ministry claimed security forces were injured and the driver of one of the vehicles panicked and ran over the protester.

One of the protesters, Mohammed Zaghloul, 21, said he saw six security vehicles heading to their site.

"It became very tense, rock throwing started and the police cars were driving like crazy," he said.

"Police threw one tear gas canister and all of a sudden we saw our people carrying the body of a man who was bleeding really badly."

Video clips posted on social networking sites also showed protesters rushing to rescue a heavily bleeding man they said was killed when a police vehicle ran over him.

Officials say more than 40 people have been killed across the country since Nov. 19, when the unrest began after a small sit-in by protesters injured during the 18-day uprising that ousted Mubarak was violently broken up by security forces. That led to days of clashes, which ended with a truce on Thursday. It wasn't clear if the melee on Saturday was an isolated incident or part of new violence by security forces trying to clear the way for the new prime minister, and protesters frustrated by what they believe are the military's efforts to perpetuate the old regime.

The military's appointment of el-Ganzouri, its apology for the death of protesters and a series of partial concessions in the past two days suggest that the generals are struggling to overcome the most serious challenge to their nine-month rule, with fewer options now available to them.

The latest crisis has overshadowed Monday's start of Egypt's first parliamentary elections since Mubarak was replaced by Field Marshal Hussein Tantawi. The vote, which the generals say will be held on schedule despite the unrest, is now seen by many activists and protesters to be serving the military's efforts to project an image of itself as the nation's saviors and true democrats.

The next parliament is expected to be dominated by the country's most organized Muslim Brotherhood group, who decided to boycott the ongoing protests to keep from doing anything that could derail the election. However, the outcome of the vote is likely to be seen as flawed given the growing unrest and the suspension by many candidates of their campaigns in solidarity with the protesters.