BAGHDAD - The United States has contacted members of a political bloc headed by former foe Moqtada al-Sadr after his parliamentary election victory put the Shi'ite cleric in a strong position to influence the formation of a new government, a top aide said.Sadr's surprise win puts Washington in an awkward position. His Mehdi Army militia staged violent uprisings against US troops after Saddam Hussein was toppled in 2003.If Sadr has a strong say in picking a new prime minister, the United States may have to work with him to safeguard its interests in Iraq, one of its most important Arab allies, which also has close ties to Iran.Dhiaa al-Asadi, a top Sadr aide, said there had been no direct talks with the Americans but intermediaries had been used to open channels with members of his Sairoon alliance."They asked what the position of the Sadrist movement will be when they come to power. Are they going to reinvent or invoke the Mahdi Army or reemploy them? Are they going to attack American forces in Iraq," he told Reuters."There's no return to square one. We are not intending on having any military force other than the official military force, police forces and security forces."The United States is believed to have some 7,000 troops in Iraq now, though the Pentagon has only acknowledged 5,200 troops. They are mostly training and advising Iraqi forces.Washington and Sadr, an Iraqi nationalist, are both opposed to Iran's deep influence in Iraq, where it arms, trains and funds Shi'ite militias and nurtures close ties with many politicians.Sadr made his surprise comeback by tapping popular resentment towards Iran and what some voters say is a corrupt political elite in Baghdad that it backs.