ISLAMABAD — Pakistan marked the 60th anniversary of its independence from British rule today amid a political crisis facing the country’s American-allied president and surging militant violence.

Artillery guns boomed at daybreak in Islamabad, and military cadets held a changing of the guard ceremony at the mausoleum of Pakistan’s founder, Quaid-e-Mohammed Ali Jinnah, in the country’s largest city, Karachi. Flag-raising ceremonies and 21-gun salutes took place in the four provincial capitals.

Some 10 million people moved across borders in one of history’s largest mass migrations as the princely states sewn together in 200 years of British rule were split into Muslim Pakistan and Hindu-majority India in 1947.

The subcontinent’s partition saw some of the bloodiest fighting of the 20th century, violence that left between 200,000 and over 1 million people dead.

In recent years, Pakistan and India have engaged in a series of negotiations aimed at normalizing relations and settling a bitter dispute over the Himalayan region of Kashmir. The two nations have fought three wars since 1947 — two over Kashmir.

The 60th anniversary is being marked tomorrow in India.

President Musharraf, who was born in the Indian capital of New Delhi, recalled in a television talk-show appearance late yesterday painful memories of his family’s move to Pakistan during partition.

“It was a train journey and my mother was very worried because dead bodies … there were dead people who could be seen on platforms where the train would stop,” Mr. Musharraf said.

Independence celebrations fall as Pakistan heads toward presidential and legislative elections.

Mr. Musharraf, a close ally of America in its war against terrorism, is seeking another term as the military head of state, but faces the toughest challenge to his rule since taking power in a bloodless coup in 1999.

Mr. Musharraf’s bid earlier this year to remove the independent-minded Chief Justice Iftikhar Mohammed Chaudhry backfired, drawing street protests. The Supreme Court struck down Mr. Musharraf’s move.

Mr. Musharraf also faces rising pressure from Washington to do more to fight Al Qaeda and Taliban militants in Pakistan’s northwest tribal region bordering Afghanistan, and a wave of suicide bombings and other violence that have killed more than 380 people since early July.

In a statement marking the anniversary, the president urged Pakistanis to reject extremism at the coming elections.

“I urge all Pakistani citizens to get involved in the electoral process and become the instruments of enlightened moderation in their beloved country,” Mr. Musharraf said.

Prime Minister Shaukat Aziz told an anniversary gathering of hundreds of government officials, school children, and others that Pakistan took pride in being the only Muslim country to have nuclear weapons.

“Our nuclear assets are symbols of our national honor and sovereignty,” Mr. Aziz said. “The nation has always displayed solidarity and unity for them. And we will never tolerate that anyone should look with a dirty eye at our nuclear assets.”

In an apparent reference to talk among American officials about possible unilateral American strikes against terrorists in Pakistan, Mr. Aziz said “we will never allow any foreign power to interfere in our frontiers.”

He said Pakistan would show respect to its neighbors, an apparent reference to India.

On the eve of Independence Day, Pakistan sent home 134 Indian prisoners who had crossed the border illegally, as part of ceremonies marking the two countries’ 60th anniversary. India was expected to return Pakistani prisoners today.