(Adds news reports on new U.S. approach, paras 8-15) By Ibon Villelabeitia BAGHDAD, Oct 21 (Reuters) - Shi'ite militias battled Iraqi police for a second day running and bombs killed more than a dozen people on Saturday, as U.S. President George W. Bush talked of changing tactics. The deaths of three U.S. Marines on Saturday brings to nearly 80 the number of American troops killed in October alone. If casualties continue to mount, this month will be one of the deadliest for U.S. forces in Iraq since the 2003 invasion. More than 2,700 U.S. soldiers have been killed in Iraq since 2003. "Our goal in Iraq is clear and unchanging: Our goal is victory. What is changing are the tactics we use to achieve that goal," Bush said in his weekly radio address. Worsening violence in the Shi'ite heartland is testing the Shi'ite-led government's ability to rein in militias and exposing a power struggle in the ruling Shi'ite coalition that threatens to further complicate the U.S. task in Iraq. "Attacks have grown significantly during the first weeks of the Muslim holy month of Ramadan," added Bush, who is facing mid-term elections in which discontent over the war is a top issue. "The last few weeks have been rough for our troops in Iraq and for the Iraqi people." The New York Times reported the Bush administration is drafting a timetable that includes specific milestones for the Iraqi government to address sectarian divisions and assume a larger role in securing the country. Citing senior U.S. officials, the Times said details of the plan, to be presented to Prime Minister Nuri Kamal al-Maliki before the end of the year and carried out over the next year and beyond, were still being worked out. "We're trying to come up with ways to get the Iraqis to step up to the plate, to push them along, because the time is coming," the paper quoted a senior Bush administration official as saying. "We can't be there forever." But a White House spokeswoman disputed the account. "The story is not accurate, but we are constantly developing new tactics to achieve our goal," White House spokeswoman Nicole Guillemard said. NEW TACTICS Bush held a videoconference with Vice President Dick Cheney, Defense Secretary Donald Rumsfeld, top White House officials and U.S. military officials in Iraq on Saturday, and a U.S. official, speaking on condition of anonymity, said the concept of a timetable for the Iraqi government did not come up at the meeting. Cheney, in a transcript of a Time magazine interview released by the White House, denied the changing tactics included looking for a way out. "We're not looking for an exit strategy; we're looking for victory. Our strategy hasn't changed," Cheney said. "And victory will be the day when the Iraqis solve their political problems and are up and running with respect to their own government, and when they're able to provide for their own security." Security seemed far away as bombs rigged to bicycles followed by a barrage of mortars killed 16 people and wounded 60 in a market in Mahmudiya, a town in the Sunni insurgent "Triangle of Death" south of Baghdad, according to Interior Ministry sources. Insurgents are battling both Iraqi government and U.S. troops and Shi'ites and Sunnis are waging a vicious sectarian conflict. On top of that is Shi'ite infighting. Iraqi Police Lieutenant Ali Naamah said violence erupted in Suwayra after some 150 Mehdi Army militiamen loyal to Shi'ite cleric Moqtada al-Sadr attacked a police station in the Tigris town 30 miles (45 km) south of Baghdad. Eight gunmen died. A Sadr spokesman said the attack on the police station was a response to a raid by U.S. troops backed by helicopters on a Sadr office that killed six people. The U.S. military said it had no reports of helicopter attacks. The fighting came a day after fierce battles between Mehdi Army militias and police in the southern city of Amara, which killed at least 25 people in two days. National Security Minister Shirwan al-Waeli met tribal leaders in Amara to try to ease the tension, caused by tribal feuding and a political struggle between Sadr's supporters and the rival Shi'ite Badr Brigade. Under mounting U.S. pressure, Iraqi Prime Minister Nuri al-Maliki has pledged to disband militias, but he is dependent on parties with ties to the militias. Sadr has a large bloc in parliament that provides key support to Maliki's coalition and moving against him could weaken Maliki's 5-month-old government. (Additional reporting by Mariam Karouny, Claudia Parsons and Caren Bohan in Washington)
