The father of a Jordanian pilot captured by militants with the Islamic State of Iraq and Syria has pleaded for his son's release.

Jordan is one of several Arab countries participating in the U.S.-led military mission to bomb fighters from the Islamist group, which holds territory in both Syria and Iraq.

First Lt. Mu'ath al-Kaseasbeh, 27, was captured after his jet crashed in northeast Syria on Wednesday during a bombing mission against the militants. The U.S. military, which commands the operation, said enemy fire was not the cause of the crash.

Kaseasbeh, who comes from a prominent Jordanian Sunni Muslim family, is the first pilot from the international coalition known to have been captured by ISIS.

The Sunni Muslim jihadist group has a history of killing enemy soldiers that it captures on the battlefield and beheading Western civilians that it takes hostage. Many of the captives it has killed are Shias or non-Muslims, but the group has also executed Sunnis for fighting alongside its enemies.

His family has pleaded for mercy.

"I do not want to describe him as a hostage. I call him a guest," his father, Saif al-Kaseasbeh, told Reuters Television.

"He is a guest among brothers of ours in Syria Islamic State. I ask them — by the name of God and with the dignity of the Prophet Mohammad, peace be upon him — to receive him as a guest of his hosts and treat him well," he said. 

Images of the pilot being pulled out of a lake and hustled away by masked jihadis underscored the risks for the U.S. and its Arab and European allies in the air campaign.

The capture — and the potential hostage situation — presented a nightmare scenario for Jordan, which vowed to continue its fight against the group that has overrun large parts of Syria and Iraq and beheaded foreign captives.

The cause of the crash was not immediately known, but the U.S. military insisted the plane was not shot down.

"Evidence clearly indicates that ISIL [ISIS] did not down the aircraft as the terrorist organization is claiming," Central Command said in a statement.

However, the pilot's uncle told journalists that the family had been told by the Jordanian government that his warplane was downed by a missile. 

Speaking at a gathering of the al-Kaseasbeh family and extended tribe in the southern Jordanian town of Karak, Younes al-Kaseasbeh said the family was told that his nephew was flying at a height of about 120 metres on a bombing mission when the militants hit him with a heat-seeking missile and his plane went down in the Euphrates River. 

He said three other warplanes in the same sortie had wanted to rescue him, but were wary of striking militants in the area for fear of killing al-Kaseasbeh, and so were ordered to return home.

U.S. Army Gen. Lloyd J. Austin III, who is overseeing all coalition military operations in Iraq and Syria, condemned the pilot's capture, saying in a statement: "We will support efforts to ensure his safe recovery and will not tolerate ISIL's attempts to misrepresent or exploit this unfortunate aircraft crash for their own purposes."


Relatives of the Jordanian pilot who was captured by ISIS after his plane was shot down congregate in front of his family's home in the city of Karak, Jordan. (Muhammad Hamed/Reuters)

A coalition official, who was not authorized to discuss the episode publicly and spoke on condition of anonymity, said the pilot was in an F-16 fighter and was able to eject.

Jordanian Information Minister Mohammad Momani earlier told the AP that the plane was believed to have been shot down.

"It is our expectation that the plane went down because of fire from the ground, but it is difficult to confirm that, with the little information we have," he said.

ISIS is known to have Russian-made Igla anti-aircraft missiles. The shoulder-fired weapon has long been in the Syrian and Iraqi government arsenals; it was used during the 1991 Gulf War by Iraqi forces to bring down a British Tornado jet, for example. More recently, militants in Chechnya have used them to down Russian helicopters.

Canadian jets fly Iraq missions

The United States and several Arab allies have been striking ISIS in Syria since Sept. 23, and U.S. and other international warplanes have been waging an air campaign against the extremists in Iraq for even longer. The campaign aims to push back the jihadi organization after it took over much of Iraq and Syria and declared a "caliphate."

Canada has provided six CF-18s, two CP-140 Aurora surveillance aircraft and a C-150 Polaris to the mission.

Jordan downed plane

This picture taken from Twitter purportedly shows a man holding the wreckage of a downed Jordanian air force plane in Syria. (Raqqa Media Center)

Foreign Affairs Minister John Baird said earlier this month that Canadian planes would only participate in airstrikes on targets in Iraq and had no plans to fly missions into Syria. 

Saudi Arabia, Jordan, Bahrain and the United Arab Emirates are participating in the Syria strikes, with Qatari logistical support.

ISIS has beheaded dozens of Syrian soldiers it captured around the country. The group has also beheaded three Americans and two Britons. In Iraq, it has shot down at least one Iraqi military helicopter, and the pilots died in the crash.

On Thursday, the Britain-based Syrian Observatory for Human Rights reported that government airstrikes in another Syrian stronghold of ISIS killed over 21 people -- including children.

The Observatory said Syrian military aircraft struck two locations in the northern town of Qabassen, including a market, causing the casualties. The death toll was likely to rise because people were still digging through the rubble to find bodies. The strike was also reported by another Syrian monitoring group.

With files from Reuters, CBC News