BERLIN (AFP) - Iraq's Prime Minister Nuri al-Maliki backs Democratic presidential candidate Barack Obama's plan to withdraw US troops within 16 months of his election, German weekly Der Spiegel said Saturday. The full interview, to be published on Monday, comes at a pivotal time in the race for the White House, with Obama set to visit Iraq on an overseas tour and Republican John McCain attacking his rival for opposing a troop surge. It follows US President George W. Bush and al-Maliki's agreement to set only a "time horizon" for military withdrawal as part of a long-term security pact. On Saturday, Britain's Prime Minister Gordon Brown also ruled out a timetable. The new US administration will take over in January, immediately after the December 31 expiry of a UN mandate authorising the presence of US troops in Iraq. Al-Maliki told Der Spiegel that Obama's 16-month window from that point was appropriate. "We feel that this would be the right timescale for withdrawal, allowing for minor adjustments," al-Maliki said in the interview. US forces should leave the country "as soon as possible," he added. "To date, the United States is struggling to agree on a concrete date for withdrawal because they view such a step as an admission of defeat, which is not the case."Bush and key ally Brown have consistently resisted calls to set a definite timetable for military withdrawal, while McCain has accused Obama of making a strategic error on past Iraq pronouncements. "When a further conditions-based withdrawal of US forces is possible, it will be because we and our Iraqi partners built on the successes of the surge strategy, which Senator Obama opposed, predicted would fail, voted against and campaigned against in the primary," he said in a statement.