Iraq's parliament approved a landmark security pact with the United States on Thursday that paves the way for US forces to withdraw by the end of 2011. The deal, which parliament linked after days of fractious negotiations to a series of promised political reforms and a public referendum next year, brings in sight an end to the US military presence that began with the 2003 invasion. Lawmakers in Iraq's 275-seat parliament passed the deal with a majority of 149 out of 198 present, Parliament Speaker Mahmoud al-Mashhadani said. It was not immediately clear if that constituted enough of a consensus to satisfy the demands of the country's most influential Shi'ite cleric Grand Ayatollah Ali Al-Sistani, whose support for the deal is crucial. But concessions linking the security pact to other issues, such as the referendum, were agreed between the country's ruling Shi'ite-led coalition and two Sunni Arab factions that have been holding up the vote for a couple of days. Under the deal, US troops will have to pull out of Iraqi cities and into bases by the middle of next year and leave the country by the end of 2011. It is expected to boost Prime Minister Nuri Al-Maliki's prestige and stature, by allowing him to continue to call on US forces to fight violence while at the same time taking credit for arranging their eventual withdrawal. “We welcome today's approval by Iraq's council of representatives of the strategic framework and the security agreement. We look forward to ratification of this vote by Iraq's Presidency Council,” a US embassy spokesman said.