Pakistan's Supreme Court has dismissed two challenges to President Pervez Musharraf's bid for reelection, but the justices are still considering several others. Pakistani lawyers have also nominated a former Supreme Court justice to run in the October presidential election as a symbolic challenge to Mr. Musharraf. Daniel Schearf reports from Islamabad.

The Supreme Court Monday dismissed without explanation one petition calling for Mr. Musharraf to immediately step down.

The other dismissed petition had argued the courts failed to do enough to stop a 2003 amendment to the constitution legalizing Mr. Musharraf's dual role as both president and chief of the military. The high court said it was too late for such a complaint.

The court is expected to rule this week on several other petitions against Mr. Musharraf, including one by opposition parties who argue he should not be allowed to run for president while chief of the military.

Also on Monday, Pakistan's Supreme Court Bar Association announced its nomination of Justice Wajihuddin Ahmed as a presidential candidate and challenger to Mr. Musharraf.

Munir Malik, the president of the legal fraternity, acknowledges Justice Ahmed is not running to win. He says the association will withdraw Mr. Ahmed's nomination if the Supreme Court rules Mr. Musharraf has the right to run for another five-year term as president.

"I don't believe it's going to come in our favor," said Malik. "But, the moral verdict is ours. That is why Waji is a candidate."

The retired Supreme Court justice is widely respected for having chosen to step down rather than swear allegiance to Mr. Musharraf's government after he took power in a 1999 military coup.

Security was tight around Pakistan's Supreme Court building Monday. Police clashed with stone-throwing protesters and arrested at least 20 who tried to reach the courthouse.

Despite the security, a man managed to spray black paint on the face of Mr. Musharraf's lawyer as he was entering the building.

Mr. Musharraf's government has come under considerable criticism for failing to stop violent extremists and for increasingly authoritarian behavior.

His failed attempt to fire the chief justice earlier this year led to massive street protests.

And he deported former Prime Minister Nawaz Sharif, who was returning from seven years in exile to mount a challenge to his presidency.

Opposition parties say hundreds of their members have been arrested in recent days, including several party leaders.

The U.S. embassy in Islamabad Monday released a statement calling the arrests "extremely disturbing" and "confusing" and said the party leaders should be released as soon as possible.