A week after gunmen stormed a church and killed 16-worshippers, Christians across Pakistan attended Sunday mass. The attack startled many in the mainly Muslim country. But many among Pakistan's minority Christian community say they had been nervous for weeks before the attack - since bombs began to fall in nearby Afghanistan.

Children play on the steps of St. Fatima's Church in Islamabad, as their parents pray inside for the 16-people killed at a Pakistani church just a week before. These youngsters seem unfazed, but the armed guards standing just steps away are a sign that things are different at churches across Pakistan.

Pereen Akhtar attended Sunday's services. She says she does not like to see the guards in front of the church, but now they are necessary to keep Christians safe while they pray.

The attack a week ago in Bahawalpur shocked the country and stole headlines from the U.S. led bombing campaign in neighboring Afghanistan. Four men stormed a Christian church there and fired more than 100 bullets at the congregation packed inside.

It was the worst attack on the country's Christian minority in recent history. Leaders across the country roundly condemned the shooting, but many Christians say they are afraid it may be part of a backlash against the government's support for the U.S. led war on terror.

"Since the [U.S. led bombing] attacks on Afghanistan, people are scared here and they were asking us before this incident what type of safety we will provide for them," said Father Simon, associate Pastor at St. Fatima's. "So we made some committees there, in their slum areas, and we asked them to take care and to be vigilant."

In the middle of Islamabad's wide streets and sprawling Western-style homes, is a packed and ramshackle slum where many of the city's Christians live. Resident Sajad Massih says Christians here had been on their guard for weeks even before the attack in Bahawalpur. He says since America began bombing Afghanistan, at least one person in every house stays awake all night and groups have begun patrolling - fearing a backlash against Christians.

Christian activist and ex-government minister for minorities, J. Salik, says President Bush's mention of the word "crusade" caused worry among many people here. He says many Muslims had misinterpreted the use of the word. He says the U.S. leader has since calmed many by working hard to clarify that he did not mean the campaign is a war between Christians and Muslims. But, he says, it still may have helped implant the element of "holy war" in the minds of some extremists.

Worshippers packed into St. Fatima's, where a banner called for them to pray for the victims of Bahawalpur. But Father Simon says his sermon also urged them to turn the other cheek. "Whatever happened in Bahawalpur we condemn, but at the same time we should not think about revenge because revenge is against Christian teaching," said Father Simon. "So as a follower of Christ we should forgive those people."

Pakistan's government has other plans. President Pervez Musharraf has promised swift justice for the perpetrators. Muslim leaders across the country roundly condemned the attack, and many say it has brought Christians and Muslims closer together. But worshippers here say news that several suspects rounded up in the government's probe have ties to extremist Muslim groups have stoked their suspicions, and they fear more attacks as the U.S. campaign continues.