Americans have been repeatedly warned to take care in Yemen, a largely lawless country known as a haven for Muslim militants and the ancestral homeland of al-Qaida chief Osama bin Laden. The country has been a key front in the U.S.-led war on terrorism. Officials said the gunman entered the complex of Jibla Baptist Hospital in the town of Jibla hiding a semiautomatic rifle under his jacket to make it resemble a child. The gunmen entered a room where the hospital director was holding a meeting and opened fire, said a statement from the Southern Baptist Convention's International Mission Board, based in Richmond, Va. Three people were killed instantly. Yemeni officials said all three were shot in the head. The gunman then headed to the hospital's pharmacy and opened fire, wounding the pharmacist, the Yemeni officials said. Jibla is in Ibb province, 125 miles south of the capital, San`a. The Southern Baptist International Mission Board identified the dead as hospital director William E. Koehn, 60, of Arlington, Texas who had planned to retire next year after 28 years of service; purchasing agent Kathleen A. Gariety, 53, of Wauwatosa, Wis.; and Dr. Martha C. Myers, 57, of Montgomery, Ala. The statement identified the pharmacist as Donald W. Caswell, 49, of Levelland, Texas. Caswell was shot in the abdomen and hospital officials said he was in critical condition and struggling for his life. The hospital was cordoned off as forensic experts gathered evidence. "We are devastated by this news," International Mission Board spokesman Larry Cox was quoted in the statement as saying. "We are moving quickly to minister to family members located in Yemen as well as the United States." Cox said no decision had been made about evacuating Americans connected with the hospital. The hospital operators said there had been no reason to believe the hospital would be the target of an attack. There were "no ongoing concerns" about an attack, said Wendy Norvelle, spokeswoman for the International Mission Board. "We've been there for 35 years." Officials said they believed the gunman was a Muslim fundamentalist. An Interior Ministry official identified the 30-year-old assailant as Abed Abdul Razak Kamel, the official Yemeni news agency Saba reported. Kamel said during interrogation that he plotted the shooting in collaboration with Ali al-Jarallah, who was arrested for shooting dead a senior Yemeni leftist politician on Saturday and whom Yemeni officials called a Muslim extremist. Another security official, speaking on condition of anonymity, said authorities were searching for a cell made up of five to eight people targeting foreigners and secular personalities in Yemen. He did not provide further details. The U.S. Embassy in San'a issued a brief statement, posted on its Web site, condemning the attack "on American citizens who have long been providing humanitarian services to Yemeni citizens at the Baptist hospital in Jibla." "We call upon the Yemeni government to bring those responsible to justice," the U.S. Embassy statement said. The embassy also asked Americans in Yemen to enhance their security and said it was requesting additional protection for them and was sending a team to Jibla to help with the investigation. The Southern Baptist missionary board said its 35-year-old hospital in Jibla treats more than 40,000 patients annually, providing care free to those cannot afford it. The board's web site said that besides their work at the 80-bed hospital, missionaries taught English and clinical skills at a nearby Yemeni nursing school. The killings are "a crime unacceptable in any religion. This contradicts Islam," said a Jibla woman who gave only her first name, Fatima, and said she used the hospital. "They cared for us and looked after us. I can't even count the number of children they treated and saved." Impoverished, factionalized, predominantly Muslim Yemen has for years been a haven for wanted Muslim extremists. Bin Laden enlisted thousands of Yemenis to fight alongside the mujahedeen of Afghanistan in their U.S.-backed war against an occupation Soviet army in the 1980s. Many returned when the Soviets withdrew, and they are a powerful political force here. In one of several such alerts, a Nov. 14 U.S. Embassy message to Americans here said the U.S. government "continues to receive credible warnings that additional terrorist activities against Western and American interests in Yemen are being planned." On Oct. 6, an explosives-laden boat rammed a French oil tanker off the coast of Yemen, killing one member of the tanker's crew, tearing a hole in the vessel and spilling some 90,000 barrels of oil. U.S. intelligence officials suspect militants with links to al-Qaida in the attack. The French tanker scenario recalled the Oct. 12, 2000, attack on the USS Cole (news - web sites), which was rammed by a small, explosives-laden boat in the southern port of Aden. Seventeen U.S. sailors were killed in that attack, which was blamed on al-Qaida. Al-Qaida also is held responsible for the Sept. 11, 2001, attacks in the United States. Yemen has signed on as Washington's partner in the war on terrorism launched after the Sept. 11 attacks.