From south and north, Iraq's Kurdish region felt pressure from two sides, as saboteurs bombed a vital bridge link to Baghdad, and Turkish troops across the border massed for a possible strike. "We won't allow it to be turned into a battleground," Prime Minister Nouri al-Maliki said Saturday of the relatively peaceful Iraqi north, a haven for anti-Turkish Kurdish guerrillas. Sectarian violence between Sunni and Shiite Muslims raged on in Iraq's center, meanwhile, as hours of mortar barrages killed eight people in a Sunni neighborhood of Baghdad that is surrounded by Shiites, and a prominent Sunni cleric was gunned down on the street. A series of explosions were heard in Baghdad late Saturday and state-run Iraqiya television reported that US warplanes were bombarding Habibiyah, a Shiite area on edge of the Mahdi Army militia stronghold of Sadr City. The US military, which has been searching for five British citizens in the area, said it was looking into the report. The US casualty toll mounted for May, third-deadliest month for Americans in the four-year-old war: A soldier wounded in a roadside bomb blast in Baghdad last Wednesday was reported to have died of his wounds, raising the month's death toll to at least 127. Tensions have heightened in recent weeks in northern Iraq as Turkey has built up its military forces on Iraq's border, a move clearly meant to pressure Iraq to rein in the rebels of the Kurdistan Workers' Party, or PKK, separatists who launch raids into southeast Turkey's Kurdish region from hideouts in Iraq. Turkey's political and military leaders have been debating whether to try to root out those bases, and perhaps set up a buffer zone across the frontier as the Turkish army has done in the past. Turkey's military chief said Thursday the army was ready and only awaiting orders for a cross-border offensive. In an interview taped for broadcast Sunday on ABC-TV's "This Week," Iraq's Kurdish president, Jalal Talabani, said Iraqi leaders had convinced the Iraq-based militants to cease their attacks, "and they did it." Al-Maliki, the Shiite prime minister, ending a visit to the Kurdish north on Saturday, also sought to ease the growing tensions. "If there are some problems, we should not rely on weapons and threats, or use violence and power because this will increase tension and deepen problems," he told a news conference in the regional capital of Irbil. Some 90 miles to the south on Saturday, a bomb heavily damaged the Sarhat Bridge, a key crossing on a major road connecting Baghdad with Irbil, Sulaimaniya and other Kurdish cities of the north, police reported. The attack appeared to be the latest by insurgents who have tried to cripple vital Iraqi supply arteries, including Tigris River bridges in Baghdad. Small cars could still cross the damaged Sarhat span with difficulty, but trucks were being rerouted to a dangerous detour through areas of Diyala province among the most active in the anti-government, anti-US insurgency, said police Brig. Sarhat Qadir. In farm fields about 40 miles to the northwest late Saturday, gunmen killed two Arab farmers and wounded six others, police in nearby Kirkuk reported. The attack may have reflected tensions between Iraq's majority Arabs and minority Kurds over future control of the Kirkuk area. The Baghdad mortar barrages slammed into Fadhil, a Sunni enclave in the Shiite-dominated eastern half of the city. The sporadic attacks began at 1:30 a.m. and lasted until 7 a.m., damaging five houses, killing eight people and wounding 25 others, police said. A policeman, speaking on condition of anonymity as he was not authorized to deal with the media, said a woman and child were among the dead. Sunni and Shiite districts frequently exchange mortar and other fire in Iraq's continuing sectarian conflict. In western Baghdad, a well-known Sunni cleric, Ali Khudir al-Zind, was killed in a drive-by shooting as he walked near his home, police said. Elsewhere in the city's western half, gunmen in two separate locations killed three people, and police found two bullet-riddled bodies of people who had been bound and blindfolded and showed signs of torture. North of Baghdad, a Sunni tribal sheik and village mayor, Rokan Mutlak al-Jibouri, whose tribe is said to be opposed to the activities of al-Qaida in Iraq, was shot to death while leaving his home for work Saturday morning, Brig. Qadir said. In all, at least 57 people were killed or found dead, including 26 bullet-riddled bodies that turned up on the streets of Baghdad bearing signs of torture - apparent victims of so-called sectarian death squads usually run by Shiite militias. The growing enmity between foreign-influenced al-Qaida extremists and nationalist Sunni insurgents exploded into gunbattles Wednesday in the western Baghdad district of Amariyah. The area remained under curfew Saturday under the watch of US and Iraqi troops. "I feel very comfortable when I see the American and the Iraqi troops because we are fed up with al-Qaida, which kept on threatening us and our businesses everyday," said Firas al-Azzawi, 32, owner of an electronics shop. "They were ordering us to close our shops because they were carrying out operations. They also have started killing Sunnis."