An arrest warrant was issued Thursday for an Australian-trained doctor who appeared in an Islamic State propaganda video which urges other medical professionals to join the jihadists, police said.

Tareq Kamleh was shown in the slick video, uploaded to YouTube in April, identifying himself as Abu Yusuf and explaining that he traveled to the city of Raqa in Syria to use his medical skills in the IS cause.

Conflicts and violence raging around the world sent the number of people forced to flee their homes soaring to a record 60 million last year, the United Nations said Thursday.

That is 8.3 million more refugees and internally displaced people (IDPs) in the world than in 2013 -- the highest-ever increase in a single year, the U.N. refugee agency said in a report titled "World at War".

The Islamic State group is in an "initial exploratory phase" in Afghanistan, the Pentagon said in a report to Congress, noting the Taliban retained its resilience in the war-torn country.

IS extremists have never formally acknowledged having a presence in Afghanistan, but fears are growing that the group is making inroads there.

A harrowing video of doctors frantically trying to save pale, limp children after a chlorine gas attack in Syria shocked U.S. lawmakers Wednesday, amid renewed calls for a no-fly zone to protect civilians.

"The Syrian government is using chlorine gas with impunity," the former U.S. ambassador to Syria, Robert Ford, told a House panel, warning that other nations like North Korea were watching the international response carefully.

Progressive Socialist Party leader MP Walid Jumblat held talks Wednesday in Amman with Jordanian King Abdullah II, amid rising fears in Lebanon and the region for Syria's Druze community.

The monarch met the Druze leader at the al-Husseiniya Palace in Amman, Jordan's state news agency Petra reported.

Despite surviving more than four years of civil war, the Syrian regime of President Bashar Assad might still fall, U.S. Defense Secretary Ashton Carter said Wednesday.

"We would like to see a transition in which Assad disappears from the scene," Carter testified before the House of Representatives' Armed Services Committee.

Syria has seen a surge in passport requests as citizens seek to flee the war-torn country, with close to a million applications lodged since January 1, media said on Wednesday.

The civil war has killed more than 230,000 people and displaced millions since it began in 2011.

The world's chemical weapons watchdog on Wednesday said all effluents from Syria's neutralized chemical weapons arsenal have been destroyed.

"The Organization for the Prohibition of Chemical Weapons welcomes the disposal of effluents resulting from neutralization operations aboard the U.S. vessel Cape Ray," the Hague-based watchdog said in a statement.

They acknowledge the risk of further violence, fear jihadists could seek to retake their home town and worry their possessions have been destroyed.

But the moment the fighting stopped, many refugees from the Syrian town of Tal Abyad could think of nothing other than going home.

The United Nations peace envoy for Syria, Staffan de Mistura, ended a three-day trip to Damascus Wednesday, condemning the deaths of civilians in both government and rebel fire.

De Mistura met government officials, including President Bashar Assad, during the visit, briefing them on consultations he is holding in Geneva with various parties to the conflict.