Islamabad, Jakarta - Pakistani protesters enraged by caricatures of the prophet Muhammad set fire to a church in Sindh province yesterday as police battled with rioters in the federal capital, Islamabad.

About 400 people attacked the church in the city of Sukkur after accusations that a local Christian had burned pages from the Qur'an, local police said.

The outrage sparked by the cartoons showed no signs of dying down, with further protests in Jakarta and Istanbul.

In Islamabad, security forces tried to block the rally organised by the MMA religious alliance by cordoning off the city centre, detaining Islamist leaders and blocking the road from Peshawar, in North-West Frontier Province.

Hundreds of soldiers were posted outside the offices of the Norwegian mobile phone firm Telenor and American fast food outlets. But hundreds of youths clashed with the police, pelting them with paving stones and scurrying down alleyways to escape plumes of tear gas.

The Danish ambassador left Pakistan and advised fellow citizens to do the same, having closed the embassy on Friday. Danish aid workers in earthquake-hit areas have also left.

As in previous cartoon protests, many seemed as angry with their leader, General Pervez Musharraf, and his alliance with the American president, George Bush, who is due to visit Pakistan next month, as they were with the caricatures.

Rashid Hafiz, 22, handed out salt to protesters whose mouths were stinging from the tear gas. "The US and its allies are the terrorists of this world. Inshallah, we will crush them," he said. Abu Omar, a 41-year-old civil servant from Rawalpindi, had brought his five sons to the march, one as young as eight. The only way to end the riots, he said, was for the Danish government to hand over the cartoonist to "the Muslim community".

"Let us decide - either to forgive him or punish him with death. If America can decide the punishment for Osama, why can't we decide that?"

The latest protests came as Saudi newspapers yesterday ran full-page apologies by the Danish newspaper that first ran the cartoons. But Jyllands-Posten said unnamed businesses had placed the advertisement, using an apology issued by the newspaper late last month. The advertisements ran in three of Saudi Arabia's main newspapers, as well as the Saudi-owned Asharq al-Awsat, which is distributed around the Arab world.

In Jakarta, hundreds of radicals attacked the American embassy, angry over the Muhammad cartoons, a statue depicting the prophet in the US supreme court and their perception that Washington wants to destroy Islam.

The 400 members of the Islamic Defenders Front arrived at the mission behind a banner reading: "We are ready to attack the enemies of the prophet." After shouting slogans and burning an American flag and a photo of George Bush, the protesters started throwing stones, rotten eggs and sticks at the perimeter gates. They then charged the gates, catching the 50 police officers off guard.

The windows of a guardpost were smashed but little other damage was done. The embassy claimed the incident was "premeditated" and "staged for television". Protests in Indonesia against the cartoons have been occurring daily, but were largely peaceful because most religious leaders preached moderation.

In Istanbul, tens of thousands of people joined a peaceful demonstration, chanting slogans against Denmark, Israel and the United States. The protest was organised by the Islamic Felicity party, whose leaders urged the world's 1.5 billion Muslims to "resist oppression".