France, US to scale up campaign against IS in Syria, Iraq

French President Francois Hollande announced on Tuesday that France and the United States would scale up strikes on Syria and Iraq, at a joint news conference with US President Barack Obama.

The announcement came after a White House meeting with Obama where Hollande sought support for his newly declared war on the Islamic State (IS) group, and as the US warned its citizens worldwide of heightened terror risks following the 13 November Paris attacks that killed 130 people.

Obama called on the European Union to implement an agreement that would require airlines to share passenger information.

Obama said there was growing recognition in Europe after the attacks in Paris that more needs to be done to prevent the flow of foreign fighters.

"As part of that, I'm calling on the European Union to finally implement the agreement long in the works that would require the airlines to the share passenger information to do more to stop the foreign terrorist fighters from entering our countries undetected," Obama said.

The hour-long talks on the campaign against IS in Syria and Iraq, as relations between Russia and Turkey - both key to resolving the Syria conflict - were plunged into crisis by Turkey's downing of a Russian warplane.

"Turkey, like every country, has a right to defend its territory and its airspace," Obama said.

Both Hollande and Obama warned against any escalation after the Russian jet downing, amid concern that the air clash could dramatically escalate tensions in the volatile region.

Hollande on Paris climate talks

Meanwhile, in an address to the French community during his Washington visit, Hollande said that going ahead with the UN climate talks in Paris is the "best response" to the 13 November attacks.

Hollande hailed the climate conference as "the most important event of recent years".

The decision to hold the 30 November-11 December climate summit is "our best response to the terrorist attacks" claimed by the IS group, he added.

"No one has asked us to suspend, delay it because in fact it is the most beautiful symbol we can imagine after the tragedy in Paris and Saint-Denis."

Some 140 to 150 heads of state or government are due to attend.

Hollande spoke for about 20 minutes before several hundred French people at the French Embassy.

Flowers still lay in front of the embassy in remembrance of the victims of the attacks.

Condemning the assaults as an attack on the French way of life, Hollande urged expatriates to "continue to live".

"Living well, eating well ... Our joie de vivre, our human qualities, our way of welcoming others, celebrating, culture - all of this was hailed by our friends around the world, and we must keep shining in this way."

Hollande's trip to Washington is part of a frantic week of shuttle diplomacy by the French leader as he tries to rally global support for increased strikes against IS.

He will hold talks with German Chancellor Angela Merkel in Paris on Wednesday and with Putin in Moscow on Thursday, before dining with Chinese President Xi Jinping in the French capital on Sunday.

The UN Security Council last week authorised "all necessary measures" to fight IS.

But the delicate diplomacy around the conflict ran into further trouble after Russia confirmed one of its fighter jets had been shot down by Turkey at the Syrian border.

The US military backed up Turkey's claim that Turkish pilots had warned the Russian jet 10 times - but failed to get a response - before shooting it down.

But Russian President Vladimir Putin accused Ankara of "a stab in the back."

"Today's tragic event will have serious consequences for Russian-Turkish relations," he said. 

Washington and Paris have stepped up their fight against IS in Syria, with France launching its first strikes from the Charles de Gaulle aircraft carrier in the Mediterranean on Monday and the US calling for more international cooperation against the IS group.

After a string of terror attacks in several countries, the US government issued a worldwide travel alert warning American citizens of "increased terrorist threats".

"Current information suggests that ISIL (another acronym for Islamic State), Al-Qaeda, Boko Haram and other terrorist groups continue to plan terrorist attacks in multiple regions," said a State Department travel advisory.