BAGHDAD - U.S. Vice President Dick Cheney, marking five years since the U.S. invasion of Iraq, reaffirmed on Monday unwavering U.S. support for the Iraqis as they continue down what he called a "difficult but historic route to democracy."

"It's good to be back in Iraq," Cheney said after an hour-long meeting with Iraqi Prime Minister Nouri al-Maliki.

Cheney, who was in Iraq 10 months ago, said the Iraqis have made legislative advances that would be vital to the country's future. He also said there was no question but there had been a dramatic improvement in security.

Al-Maliki, speaking through an interpreter, also cited security improvements and said he and the vice president had talked about negotiations under way to spell out the legal basis for the presence of U.S. troops on Iraqi territory and to establish the legal rights and obligations of the troops, the so-called "status of forces agreement."

Cheney landed at Baghdad International Airport, then flew by helicopter into the dusty, heavily secured Green Zone for talks with U.S. military and diplomatic officials and the Iraqi prime minister. It is Cheney's third vice presidential trip to Iraq where 160,000 American troops are deployed and the U.S. death toll is nearing 4,000.

Cheney's first meeting was a classified briefing with U.S. Ambassador Ryan Crocker and Gen. David Petraeus, the top U.S. military commander in Iraq who met him at the airport. Crocker and Petraeus are scheduled to travel to Washington next month to give a status report on the war.

For security reasons, Cheney officials divulged few details about the vice president's schedule and asked reporters not to report on his location until he had moved on to another. Cheney was expected to make stops throughout the country, speak to troops and spend time with other Iraqi leaders.

Cheney's motorcade zigzagged through Baghdad to meetings as helicopter gunships circled overhead. Explosions were heard in parts of the city, but none were near the vice president.

"There is still a lot of difficult work that must be done," Cheney said after sitting down with Abdul-Aziz al-Hakim, the leader of the Supreme Islamic Iraqi Council and one of the most powerful politicians in the country.

"But as we move forward, the Iraqi people should know that they will have the unwavering support of President Bush and the United States in consolidating their democracy," Cheney said.

Oman was scheduled to be the first stop on Cheney's 10-day trip to the Mideast, but on Sunday night, he left Air Force Two parked on a tarmac in England and boarded a C-17 for the final five and a half hours of the 13-hour flight to the Iraqi capital.

The future of Iraq will be discussed in his closed-door talks with leaders of Oman, Saudi Arabia, Israel, the Palestinians and Turkey. Cheney's discussions at each stop also will touch on Iran's nuclear program and its desire for greater influence in the region, high oil prices and the pursuit of an Israeli-Palestinian peace deal that President Bush wants to see before he leaves office.

Cheney, who is traveling in Iraq with his wife, Lynne, and daughter, Liz Cheney, last visited the country in May 2007 before the president's buildup of more than 30,000 additional U.S. troops was in full gear. Bush dispatched the extra troops to reduce violence so Iraqi politicians could forge agreements that would bring minority Sunni Arabs into the government and weaken or end the insurgency.

Security has improved markedly since last summer when the last of the five Army brigades arrived in Iraq to complete the military buildup, but Iraqi politicians are still in gridlock.

Cheney advisers say the vice president will highlight the reduction in violence and praise the fragile Iraqi government for passing some legislation aimed at national unity. In short, Cheney will compare and contrast Iraq before and after the increase in troops. He'll tell Iraqi leaders that they are on the right track and have made strides, but that now is the time to do more.

The Iraqis do not yet have a law for sharing the nation's oil wealth among the Shiites, Sunnis and Kurds, a law that the Bush administration believes will trigger multinational energy companies to invest in exploration and production in Iraq.

Also unfinished is a plan for new provincial elections. Iraq's presidential council, which must give its nod to laws passed by the Iraqi parliament, rejected a plan for new elections last month, shipping it back to the legislature.

The rejection, a setback to the U.S. campaign for national reconciliation, came despite Cheney's last-minute phone call to the main holdout on the three-member panel: Vice President Adel Abdul-Mahdi, a Shiite. Cheney was expected to speak with Abdul-Mahdi and the other two members of the council, President Jalal Talabani, a Kurd, and Sunni Vice President Tariq al-Hashemi, while in Iraq.

The war is entering its sixth year. It was on March 17, 2003, that Bush gave Saddam Hussein 48 hours to relinquish power. Three days later, U.S.-led forces began invading Iraq. The anniversary of the invasion is March 19 in the United States and March 20 in Iraq.

Bush and Cheney have just 10 months before they hand off the war to the next U.S. president.

Democratic rivals Sens. Hillary Rodham Clinton and Barack Obama have said they would begin withdrawing forces quickly if elected. Expected Republican presidential nominee, Sen. John McCain, who also is visiting Iraq, is more apt to continue Bush's strategy of bringing troops home only as conditions warrant.

It was unclear if Cheney and McCain would cross paths during their visits to Iraq.