WASHINGTON (AFP) - Republican presidential hopeful Mitt Romney said in an interview aired Sunday that US withdrawal from Iraq is "precipitous" and blamed Obama for failing to leave some US forces behind. "I think we're going to find that this president, by not putting in place a status-of-forces agreement with the Iraqi leadership, has pulled our troops out in a precipitous way and we should have left 10-, 20-, 30-thousand personnel there to help transition to the Iraqi's own military capabilities," Romney said in an interview with Fox News Sunday. Romney comments airs after the last US troops crossed out of Iraq into Kuwait, nearly nine years after a US invasion that resulted in the deaths of 4,474 US troops and tens of thousands of Iraqis. US military commanders advocated leaving a residual US force in the country to train and support the Iraqi military, but Prime Minister Nuri al-Maliki refused to extend legal protections to US troops under a status of forces agreement, scotching that option. Among the unresolved questions raised by the US departure is the degree of Iranian influence over Iraq's Shiite dominated government and how sectarian tensions will play out. "I'm very concerned in this setting. I hope it works out," Romney said. Romney has been an on-again, off-again leader in the Republican fight to nominate a candidate to go up against Obama in the November 2012 presidential elections. Former US envoy to China Jon Huntsman, one of Romney's rivals for the party's presidential nomination and the Republican candidate with the strongest foreign policy credentials, also assailed the withdrawal. "President Obama's inability to reach a security agreement in Iraq is a product of the administration's failures in the region," said Huntsman spokesman Tim Miller. "Governor Huntsman would have supported an agreement that left a small troop presence that could have assisted with the training of Iraqi security forces and vital counter-terror efforts," Miller said.