President General Pervez Musharraf imposed a state of emergency and reporting restrictions on non-state media, and dismissed the Supreme Court chairman on Saturday citing growing militant activities in the country. But lawyers said the moves were illegitimate.
Earlier on Monday, police clashed with opposition lawyers using teargas and batons. Foreign media reported, citing witnesses, that 350 people were arrested.
The United States has postponed defense talks with Pakistan, which were due this week, Reuters reported.
"Pakistan is a country of great strategic importance to the United States and a key partner in the war on terror. However, the actions of the past 72 hours have been disturbing," U.S. Defense Secretary Robert Gates said on a visit to China as quoted by the agency.
The opposition and many ordinary Pakistanis said they believed Musharraf was thereby trying to preempt a Supreme Court ruling that the president had been ineligible to stand for reelection last month.
Musharraf won the presidential poll on October 6, but the Supreme Court said the official results would be published after two presidential candidates' complaints have been examined.
Musharraf will not give up his military title, which he had earlier vowed to do in the event of his reelection, a senior government official told Agence France-Presse.
"President Musharraf has promised the Supreme Court to take off his military uniform before taking the presidential oath, but this promise is not valid as a state of emergency was imposed," a deputy information minister, Tariq Azim, said.
General Musharraf seized power in a military coup in 1999. He has since retained his presidential and military titles, as well as the right to dissolve parliament and dismiss the government.
