US Senator John McCain has gone to Baghdad in a previously unannounced visit to the Iraqi capital.
Senator McCain is a strong supporter of the "surge"
Mr McCain - set to be the Republican's presidential candidate in November - will meet with US and Iraqi officials during his trip.
Mr McCain is also scheduled to visit London, Paris and Israel this week.
The senator is known for his strong support of current US policy in Iraq, and was one of the most prominent proponents of the "surge" strategy.
This will be Mr McCain's eighth visit to the country since the US-led invasion began in 2003.
He is scheduled to hold meetings with Iraqi Deputy Prime Minister Barham Saleh and Gen David Petraeus, the commander of US troops in Iraq.
During the rest of his tour he will meet British Prime Minister Gordon Brown, French President Nicholas Sarkozy and Israeli Prime Minister Ehud Olmert
He is being accompanied on his trip by Senator Joe Lieberman and Senator Lindsey Graham, close allies of Mr McCain and fellow supporters of a continued US troop presence in Iraq.