German Chancellor Gerhard Schröder has said he doubts his conservative challenger's pledge that she will keep German troops out of Iraq if she is elected this autumn, in an interview published Wednesday. "I hear that Ms (Angela) Merkel is of another opinion but I have my doubts," Schröder told the daily Neue Presse in his hometown of Hanover. Schröder, who campaigned against the US-led invasion, said he was convinced that if his opponent in the 2002 election Edmund Stoiber had won, German soldiers would now be fighting in Iraq. The German leader's outspoken opposition to the Iraq war -- six months before it began -- was widely credited with giving him the crucial boost to win a tight re-election race. Schröder has attempted to bridge the rift with Washington over his strident stance against the war by committing Germany to training Iraqi security forces in the neighboring United Arab Emirates. Although Merkel's Christian Democratic Union has a double-digit lead in the polls, a survey published last month in Der Spiegel news weekly found that two-thirds of voters do not trust her promise not to send troops to Iraq. Schröder's Social Democrats (SPD), who have plummeted in popularity over their economic and job market policies, have attempted to put an accent on foreign and security policy issues in the campaign for the September 18 election.