US Secretary of State Condoleezza Rice has praised the Iraqi government during a surprise trip to Baghdad.Ms Rice said she had travelled to Iraq to promote new Sunni and Kurd support for the US backed Shi'ite government.At a press conference, she said she sees signs that Iraqi Prime Minister Nouri al-Maliki's government-led assaults on militia forces last month have brought sectarian and ethnic groups together in an unprecedented way.She said she wants to capitalise on that cohesion.Her main goal is to spotlight what she calls encouraging political signs following the crackdown in Basra.Ms Rice also said she did not know how seriously to take a threat of all-out war by Iraqi cleric Moqtada al-Sadr, and rebuked him for threatening violence while living abroad.Sadr threatened on Saturday to launch an "open war until liberation" against the US-backed government if it continued a month-old crackdown on his followers.The threat from the Shi'ite cleric was followed by what the US military called the heaviest fighting for weeks in his east Baghdad stronghold of Sadr City.A military spokesman said US forces had killed 20 fighters overnight on Saturday in a series of gunbattles and helicopter missile strikes in Sadr City, the east Baghdad slum that is a stronghold of Sadr's militia."He is still living in Iran. I guess it's all out war for anybody but him," Ms Rice said of Sadr, who has not appeared in public in Iraq in nearly a year."His followers can go to their death and he will still be in Iran."Ms Rice is also set to meet Persian Gulf diplomats in Bahrain, and a wider group of Arab states and others in Kuwait.