Security had been increased in churches ahead of Christmas celebrations around this mostly Islamic nation, which has seen a string of Islamic militant attacks targeting Christians this year. Also Wednesday, police said they found explosives and ammunition near a church in Pakistan's capital, Islamabad. Church officials feared they had been the intended target of an attack. In Chianwala, about 40 people, mostly women and children and all Pakistanis, were attending a Christmas Day service at the church when the attack occurred Wednesday evening. The two attackers escaped after the attack, said Iftikhar Ahmed, spokesman for Pakistan Interior Ministry. Four of the injured were in critical condition, said Malik Mohammed Iqbal, chief of police in the nearby city of Gujranwala. Witnesses said the attackers wore burqas, the traditional all-encompassing garment worn by women in some Islamic countries, said Amanat Ali, a police official in Daska. But it was unclear whether the attackers were women or disguised men. Ali said witnesses reported the attackers were taller than most women. Male Islamic militants in neighboring Afghanistan have worn burqas to hide their identities in at least one recent attack there. Since Pakistan lent its support to the U.S.-led military campaign to overthrow Afghanistan's hard-line Taliban, attacks on Christians by suspected Islamic militants have killed about 30 people and injured at least 100. The United States is widely identified as a Christian country. On Wednesday, Pakistani security officials said they found a shopping bag in bushes containing two handmade grenades and 20 shell casings about 100 yards from Islamabad's St. Thomas's Protestant Church. Cheema, of the Interior Ministry, said the motive for leaving the weapons was not certain. In the days leading up to Christmas, more than half-dozen policemen cradling rifles had been posted around the church. Church officials said they feared the weapons had been left as part of a planned attack on them. Still, Christmas services were held as scheduled. ``It's God's promise that he will be with us,'' the church's pastor, Rev. Irshad John, said ``It was God who changed the plans of those people.'' There have been four deadly attacks on Christians in Pakistan this year. The last was on Sept. 25, when gunmen entered the offices of a Christian welfare organization in Karachi, tied seven employees to their chairs and shot each in the head, execution style. On March 17, a grenade attack on Protestant church in Islamabad killed five people, including a U.S. Embassy employee and her 17-year-old daughter. On Aug. 5, assailants raided a Christian school filled with foreign children in Murree, 40 miles east of Islamabad. Six Pakistanis were killed, including guards and non-teaching staff. And on Aug. 9, attackers hurled grenades at worshippers at a church on the grounds of a Presbyterian hospital in Taxila, about 25 miles west of Islamabad, killing four people.