ISLAMABAD, Pakistan — Pakistan's ruling coalition teetered on the brink of collapse as the two main partners squabbled over a successor to ousted President Pervez Musharraf.

Former Prime Minster Nawaz Sharif, who heads the junior partner in the coalition, demanded the dominant Pakistan People's Party slash the president's powers before he would support its candidate.

Asif Ali Zardari, head of the PPP and widower of the party's assassinated leader Benazir Bhutto, agreed Saturday to run for the presidency.

Sharif also pushed forward the deadline for restoration of dozens of judges sacked by Musharraf _ another key issue dividing the two main parties since they forced the president from power less than a week ago.

Still pressure was building for the two sides to end differences that appeared increasingly irreconcilable. ....