A car bomb has exploded in Baghdad's heavily fortified Green Zone complex, killing three people and injuring six.
The vehicle entered the Green Zone, which houses the US and British embassies and the Iraqi government, by an entrance frequently used by the media and others.
Police said the car exploded as it was being searched at the first checkpoint inside the zone.
Those killed and injured were believed to be members of the Iraqi army.
In the west of the country, thousands of US troops have widened their hunt for al-Qaeda insurgents in a new offensive along the Euphrates valley.
Some 2,500 US soldiers launched the operation around Haditha, Haqlaniyah and Barwana in the latest and largest such sweep in Al-Anbar province this year.
Al-Qaeda has urged Sunni Muslims to step up attacks on US forces during the month of Ramadan, which has previously seen some of the bloodiest attacks by militants.
The Iraqi group, led by Jordanian Abu Musab al-Zarqawi, said in a statement that the 'gates of heaven are open' during the fasting month, which began today for most Sunnis in the Middle East. Shi'ites mark the start of the month on Wednesday.
The statement was posted on a website often used by the group.
Earlier, a militant group claimed it had shot down a US drone west of the Iraqi capital.
The group calls itself The Earthquakes Brigades of the 1920 Revolution, the military wing of the Islamic Resistance Movement in Iraq.
It claimed the unmanned craft was shot down in Fallujah.
The authenticity of the statement could not be confirmed, but yesterday the US military confirmed the loss of an unmanned plane which crashed into a house in Fallujah.
