The image of US President Barack Obama jogging down the steps of Air Force One onto the tarmac in Ankara was a diplomatic victory for Turkey, which often felt ignored or taken for granted under the previous US administration.

The overwhelmingly Muslim country that is a member of NATO and is working to join the European Union has long been a US ally, and Obama seeks its help in the US pullout from Iraq, turning around the Afghanistan war and blocking Iran's nuclear ambitions.

The country, seen as a bridge between the West and the Muslim world, has also tried to bring about peace between Israel and both Syria and the Palestinians.

The invasion of Iraq had strained the long friendship between the US and Turkey, but Obama's visit is expected to open a new chapter.

He arrived late Sunday, and was greeted by US diplomatic staff and Mehmet Simsek, the Turkish economy minister, before stepping into a black limousine.

Hours before his arrival, Obama told EU leaders to accept Turkey as a member, saying it would be a positive sign to the Muslim world.

Turkey began negotiations to join the EU in 2005, but the talks have stalled amid bickering on issues that include human rights and Turkey's refusal to recognize EU-member Cyprus. France, Austria and other nations also have concerns over letting a poor and populous country with a predominantly Muslim population into the EU.

Obama was also instrumental in overcoming Turkish objections to Danish Prime Minister Anders Fogh Rasmussen being selected as NATO's new secretary general, Turkish leaders said. Turkey had opposed Fogh Rasmussen's candidacy, saying the Dane angered Muslims around the world by supporting the right to caricature the Prophet Muhammad.

Turkish Prime Minister Recep Tayyip Erdogan said late Sunday that Obama's "guarantorship" helped resolve concerns over Fogh Rasmussen's selection.

"He put forth a lot of positive energy," Erdogan said. "We responded positively to this. We hope that the promises made are kept."

As part of tight security measures in Ankara, authorities blocked off a street leading to his hotel, deployed riot police and set up barricades. Military jets and police helicopters were instructed to patrol a no-fly zone over Ankara's skies, and police dogs checked areas near Obama's hotel for explosives.

Obama travels Monday to Istanbul for two days, and officials in the city on the Bosporus Strait said nearly 9,000 police officers would be on duty.