BAGHDAD (AP) ― Vice President Joe Biden arrived on a surprise visit to Iraq late Tuesday in a trip designed to chart a new relationship between the two countries after all American forces have left the country in just over a month.

After nearly nine years of war, the U.S. now must navigate a future without American troops in Iraq. Iraq’s vast oil resources, the massive U.S. Embassy presence here and Iraq’s strategic location in the Middle East ― next to Iran ― ensure American interest will remain high in Iraq even after the troops are gone.

“It’s good to be back,” Biden said during a meeting at the embassy with U.S. Ambassador to Iraq James F. Jeffrey and the top American commander in Iraq, Gen. Lloyd Austin. Austin and Jeffrey met Biden at the airport when he landed.

Baghdad and Washington failed earlier this year to come to an agreement on keeping a small American military presence in Iraq next year, meaning all U.S. forces must be out of the country by Dec. 31. Some 13,000 U.S. troops remain, down from a one-time high of about 170,000.

The issue of what type of military relationship Iraq and the U.S. will have next year and into the future is expected to dominate Biden’s visit. His trip will also lay the groundwork for Prime Minister Nouri al-Maliki’s Dec. 12 visit to Washington. Biden also will take part in a ceremony commemorating the sacrifices of U.S. and Iraqi troops.

Iraqi leaders have said they want U.S. military training help for their security forces but have been unable to agree on what type of help they’d like or what protections they would be willing to give the American military trainers.

The U.S. ambassador told reporters that the U.S. is trying to assess how “we can support Iraq, particularly to develop their conventional capabilities, and to continue the fight against terror.”

“This is a very, very important joint priority of ours. The al-Qaida in Iraq organization is still active particularly in the north but they strike throughout the country,” he said.

In the week leading up to Biden’s visit, Iraq has seen an uptick in violence that has renewed concerns about the abilities of the country’s security forces.

A suicide bomber slammed a car packed with explosives into the gate of a prison north of Baghdad on Monday, killing at least 19 people. On Saturday a string of explosions killed 15 people. Three days earlier, a triple bombing in the southern city of Basra killed 19 people.

Many U.S. and Iraqi officials are concerned insurgents may use the transition period when American troops depart to launch more attacks in a bid to regain their former prominence and destabilize the country.

The U.S. Embassy will have 157 American military personnel in charge of facilitating weapons sales to Iraq, and then about 700 civilian contractors around the country helping train Iraqis on the weapons they’ve purchased. U.S. Marines will also guard the embassy, which is the largest American embassy in the world.

Biden’s visit also will likely touch on Syria and Iraqi concerns over the turbulence that has engulfed Iraq’s western neighbor. While Washington has harshly criticized Syrian President Bashar Assad’s bloody crackdown that has killed more than 3,500 people, Baghdad has taken a more conservative approach.

Iraq was one of only three countries to fail to support sanctions on Syria approved by the 22-member Arab League Sunday. Iraqi Foreign Minister Hoshyar Zebari said in an interview with the Associated Press Monday that Iraq was not acting out of pressure from neighboring Iran, with which Iraq has close ties.

“We took that decision out of the national interest of Iraq. So this doesn’t mean that we condone the regime’s actions against its civilians or demonstrators or that we don’t care about the freedom of the Syrian people,” Zebari said. “But there are certain self interests here for Iraq.”

Zebari noted the hundreds of thousands of Iraqi refugees living in Syria, as well as the long-standing economic ties along the countries’ extensive border.

Iraq leaders are also deeply worried about what type of government might replace Assad. A conservative Sunni-led regime with ties to Saudi Arabia could be a disaster for Iraq, which is still wrestling with Sunni-Shiite problems of its own.

The U.S. vice president and Iraqi leaders will also likely discuss the fate of Ali Mussa Daqduq, a Lebanese Hezbollah commander linked to the death of four American troops in Karbala in 2007.

Last week, the U.S. handed over all the remaining detainees in its custody to the Iraqi government as required by the 2008 agreement with the exception of Daqduq. U.S. officials are worried that if he is transferred to Iraqi custody, he could escape or simply be allowed to walk free.

The Obama administration has been weighing whether to transfer Daqduq to the United States but that would require the approval of the Iraqi government.