ISLAMABAD, Pakistan - Pakistan's Election Commission said yesterday that a key opposition leader, Nawaz Sharif, cannot run in parliamentary elections next month. The ruling eliminates the former prime minister's chances of returning to office.

The decision leaves Sharif with no further avenue for appeal and denies him a platform in parliament to continue his campaign against his archrival, President Pervez Musharraf, the former army chief who ousted him in a 1999 coup.

Sharif's party blasted the decision as an attempt to sideline a leading threat to Musharraf before the Jan. 8 elections, which Western governments hope will produce a government stable enough to fight Islamic extremism.

"This also shows that they are still afraid of his popularity and cannot face him," Sharif spokesman Ahsan Iqbal said. "This also shows that there is no level playing field in these elections."

The Election Commission, which was appointed by Musharraf, upheld a decision by a local election official to disqualify Sharif based on his alleged involvement in a corruption case and charges against him relating to the 1999 coup against him.

Sharif has been leading his Pakistan Muslim League-N's parliamentary campaigning. He is demanding that Musharraf restore the Supreme Court judges he fired during a 42-day state of emergency that was lifted over the weekend.

Sharif's party decided against an election boycott after failing to muster support from other opposition groups for united action. The party did not announce any change after the Election Commission decision.

However, a coalition of smaller anti-Musharraf groups, including Jamaat-e-Islami, Pakistan's largest Islamic party, said yesterday it would boycott the vote.

It said the elections would not be fair unless the judges were reinstated, restrictions on civil liberties Musharraf put in place under the emergency were revoked, and he resigned.

Sharif was exiled to Saudi Arabia and Britain after his ouster by Musharraf. Like Benazir Bhutto, who heads the Pakistan People's Party and is another two-time former prime minister, Sharif returned home to be involved in the elections.

The commission rejected Sharif's appeal Monday, commission spokesman Kanwar Dilshad said yesterday. The chief election commissioner also rejected an appeal by Sharif's politician brother, Shahbaz Sharif, of the rejection of his nomination for the balloting, Dilshad said.

Addressing an election rally in the southern city of Mirpur Khas, Bhutto said the departing government, run by pro-Musharraf parties, "has given only terrorism, unemployment and inflation to this country."

She praised Musharraf for keeping promises to quit his post as army chief and hold elections on time, but said the real test would be whether the elections were fair.

"We will see on Jan. 8 whether this promise is fulfilled or not," she said.