ISLAMABAD, Pakistan — Pakistan’s main ruling party is proposing major constitutional changes that would curb the dwindling authority of President Musharraf. But winning agreement will be difficult and could strain an already fraying coalition government.

According to a copy obtained by the Associated Press, the draft amendments would, among other changes, end presidential power to declare war and reverse Mr. Musharraf’s firing of senior judges — an action last year that, along with increasing violence by Islamic militants, caused his popularity to slide.

The new civilian government, led by the party of the slain Premier Benazir Bhutto, took power two months ago after defeating Mr. Musharraf’s allies in parliamentary elections, ending eight years of military domination.

But while the coalition partners remain united in their animosity toward the American-backed Mr. Musharraf, forging quick agreement on the proposed 80 constitutional amendments appears unrealistic.

Changes to the constitution require a two-thirds majority in both houses of parliament, a tough threshold even if the four coalition parties reach consensus on amendments. Together they don’t even have a simple majority in the upper house.

Also yesterday, Denmark’s intelligence service cast blame on Al Qaeda for an attack near its embassy in Pakistan that investigators said was carried out by a suicide bomber.

No one has claimed responsibility for the car bomb, which killed six people. But Danish authorities said the terror network or one of its affiliates was likely behind the explosion, which came just weeks after the terrorist group threatened Denmark over caricatures of the Prophet Muhammad reprinted earlier this year in newspapers in that country.