US Secretary of State Condoleezza Rice has urged Iraqis to consider ethnic and religious differences a strength, not a weakness, on a surprise visit to Iraq.
Condoleezza Rice said she wanted Iraqis to create a united country
"Differences of history or tradition, culture or ethnicity... can be a strength rather than a handicap" in a democracy, she said in Baghdad.
Ms Rice arrived amid heavy security, her visit kept secret until she landed in the northern Iraqi town of Mosul.
Violence continued unabated, with both US and Iraqi forces killed in attacks.
Three US marines died in two separate incidents, and three Iraqi policemen were killed in Baquba.
Ms Rice met Iraqi Prime Minister Ibrahim Jaafari and was briefed by US officials on security progress ahead of elections scheduled for 15 December.
She said she wanted to urge Iraqis to reach out across sectarian lines.
Speaking to reporters, she said her main aim was to encourage Iraq's various political and religious groups to create a single, united country where everyone felt "fully protected".
"The US is not going to support any particular political candidate," she said.
"I want to talk about the importance of reaching across the sectarian divide, and the future of Iraq has to be one which includes everyone."
She said she hoped to encourage greater Sunni participation in these parliamentary elections. The main Sunni parties boycotted the vote last January.
On Friday the US military announced two US marines had been shot dead on Thursday during operations in Khaldiya, west of Baghdad, while a third was killed by a bomb near the Syrian border.
A car bomb in Baghdad on Friday caused only a few injuries, initial reports said.
During her tour, Ms Rice will launch an initiative aimed at promoting democratic and economic reform in the region.
In Bahrain, she will unveil two new programmes:
- A $50m (£29m) Fund for the Future aimed at aiding small businesses in the region
- A $35m (£20m) Foundation for the Future that aims to promote political reform in the Middle East and the Arab world.
Ms Rice hopes the two schemes will help push forward President George W Bush's stated foreign-policy goal of spreading democracy and freedom.
But the US secretary of state is also expected to face tough questions concerning America's moral authority, says the BBC's Jonathan Beale.
Specifically, she will be quizzed on the treatment of prisoners, following damaging claims the US has set up secret prisons to hold Islamic extremists.
The US administration has refused to confirm or deny the reports but insists that it does not torture prisoners and operates within the law.
Ms Rice is due to go on to Bahrain, Saudi Arabia and Israel to promote moves towards economic and political reform.
Her visit to Israel and the Palestinian territories also comes at a difficult time.
In Tel Aviv she will hold talks with Israeli and Palestinian leaders.
There she will press both sides to capitalise on Israel's withdrawal from the Gaza Strip.