US President-elect Barack Obama has called Iraq's prime minister and stressed his commitment to a responsible withdrawal of American forces from Iraq, the government said. During Wednesday's call, Obama thanked Prime Minister Nouri al-Maliki and the Iraqi government for its efforts in gaining parliament's approval of a security pact that sets out a three-year timeframe for a full withdrawal of US troops, according to a statement. Obama also gave assurances he's committed to respecting Iraq's sovereignty and to a responsible withdrawal of US forces, al-Maliki's press office said. Nick Shapiro, a spokesman for the Obama transition team, said the president-elect returned calls to six world leaders, including al-Malaki, to express his appreciation for congratulations on his election. He did not give details about the conversations.