ANTALYA, TURKEY: President Barack Obama's talks with world leaders in Turkey this week have taken on new urgency following a series of horrific attacks in Paris carried out by the Islamic State group, sparking global anxiety about the militant group's reach.

The crisis in Syria, where the Islamic State group has taken root, was already high on the agenda at the meeting of 20 leading industrialised and emerging-market nations. But the violence in Paris that killed at least 129 people and injured 352 will dramatically change the dynamic of the talks in Antalya, Turkey, a seaside resort city just a few hundred miles from the Syrian border.

Obama arrived in Turkey Sunday morning after an overnight flight from Washington, and was greeted on the tarmac by Turkish officials and the US ambassador. He was scheduled to discuss the terror attacks in a meeting with Turkish President Recep Tayyip Erdogan before beginning broader discussions with Group of 20 leaders.

French President Francois Hollande said Islamic State militants were behind the attacks and the extremist group claimed responsibility Saturday. The White House said it had "no information to contradict the initial French assessment."

Obama's itinerary, which also includes stops in the Philippines and Malaysia, was not expected to be impacted by the terror attacks. There were also no immediate changes in his plans to travel to Paris in two weeks for a high-stakes climate conference, a meeting of world leaders that will require an enormous security presence.

Security is expected be extremely tight in Turkey as leaders gather for two days of talks in Antalya, where several suspected Islamic State militants were recently detained.

Ahead of Obama's talks in Turkey, Secretary of State John Kerry met in Vienna with his counterparts from Russia, Turkey and other nations with a stake in Syria. The diplomats agreed on a timeline for a political transition in Syria that is aimed at ending the country's 4 ½ year civil war, though key details — including the status of Syrian President Bashar Assad — remain unresolved.

More 250,000 people have been killed in the clashes between rebels and forces loyal to Assad. Eleven million people have been uprooted from their homes, sparking a massive migration crisis in Europe that is also expected to be on the agenda at the G-20 meeting.

The president's first meeting in Turkey is with Erdogan, the Turkish leader whose ties with the White House have become increasingly strained. Their meeting wasn't announced until shortly before Obama's departure, a underscoring the "very tense nature" of the US-Turkey relationship, according to Heather Conley, a Europe expert at the Centre for Strategic and International Studies, a Washington think tank.

While Erdogan shares Obama's desire to get Assad out of power in Syria, the two leaders have disagreed over tactics.

"The US and Turkey do not align on the dimension of the Syrian campaign," Conley said.

Erdogan has been frustrated by Obama's willingness to use military force against the Islamic State, but not against Assad. The US, meanwhile, was irked by Erdogan's reluctance to join the campaign against IS, though Turkey eventually decided to start bombing the militants this summer and also allowed the US to launch its own airstrikes from key bases in the county.

Obama's dealings with Russian President Vladimir Putin over Syria have been even more complicated. As Assad's biggest benefactor, Russia has essentially propped up the Syrian leader throughout the crisis. Until Putin is willing to abandon Assad and accept new leadership in Syria, it's unlikely a political solution can be reached.

Despite Obama's vow to isolate Putin in retaliation for Russian aggression in Ukraine, the president agreed to meet with his longtime foe in New York earlier this year to discuss Syria. The slight optimism U. S. officials expressed after the meeting was quickly dashed when Russia began launching its own airstrikes in Syria, raising the prospect of a proxy war with the US

While Putin says his country's forces are targeting the Islamic State, US officials have accused Russia of instead going after forces fighting Assad in a bid to protect the Syrian leader.

Obama and Putin won't hold another formal meeting in Turkey, but White House officials said the leaders would have plenty of time to talk on the sidelines of the G-20.