Air strikes on a convoy of the Islamic State group killed at least 40 jihadists in central Syria at the weekend, a monitoring group said Sunday.

The Britain-based Syrian Observatory for Human Rights said unidentified warplanes hit the 16-vehicles motorcade overnight between Saturday and Sunday in Hama province, killing the jihadists.

The Observatory, which monitors the war in Syria and has a network of sources on the ground, was not immediately able to say whether the raids were carried out by Russian warplanes or Syrian regime ones.

"But they don't belong to the coalition led by Washington," said Observatory chief Rami Abdel Rahman.

Charred bodies of IS fighters were found at the scene, he added.

Syrian regime aircraft bombard almost daily the eastern countryside of Hama where IS has positions.

Abdel Rahman said the convoy was hit as it was heading from the self-declared IS capital of Raqa in northern Syria to the Hama countryside.

Russia, a key ally of the Syrian regime of President Bashar al-Assad, has been carrying out a campaign of air strikes against his opponents since September 30.

Last year, a US-led coalition launched an air campaign against IS which controls swathes of Syria and neighbouring Iraq.

Khorasan Group leader dead in Syria air strike: US
Washington (AFP) Oct 18, 2015 - The leader of a group of Al-Qaeda veterans which Washington calls the Khorasan Group has been killed in a coalition air strike in Syria, the Pentagon said Sunday, proclaiming it another victory against a shadowy outfit it says targets the United States.

Sanafi al-Nasr, a Saudi national and trusted Al-Qaeda militant, was killed in an air attack in the northwest of the country on Thursday, according to the Pentagon.

"This operation deals a significant blow to the Khorasan Group's plans to attack the United States and our allies," Secretary of Defense Ash Carter said in a statement.

The Syrian Observatory for Human Rights, a Britain-based monitoring group, had reported al-Nasr's death on Friday, saying he was killed in a strike in Aleppo province.

Al-Nasr -- also known as Abdul Mohsen Abdullah Ibrahim al-Sharikh -- was listed as a "specially designated global terrorist" by the US Treasury Department in 2014.

He had been erroneously reported dead in the past.

"The United States will not relent in its mission to degrade, disrupt and destroy Al-Qaeda and its remnants," added Carter.

The Pentagon described al-Nasr as a "long-time jihadist" who funneled money and fighters for Al-Qaeda and said he was the fifth senior Khorasan Group leader killed in the last four months.

US strikes in Syria have largely targeted jihadists in the Islamic State group.

But Washington has occasionally also gone after what it brands the Khorasan Group, which it says is a cell of senior Al-Qaeda veterans charged with planning attacks in the West.

Officials say Khorasan is part of Al-Qaeda's Syrian branch, Al-Nusra Front, although experts and activists cast doubt on the distinction between the two groups.

In a September interview, US President Barack Obama listed Khorasan among "immediate threats to the United States," warning that "those folks could kill Americans."

Khorasan members have traveled from Central Asia and elsewhere in the Middle East to Syria to plot attacks on the West, the United States says.

The Pentagon said al-Nasr was involved in myriad jihadist activities.

In 2012, he oversaw Al-Qaeda's finances and a year later relocated to Syria, the US says.

He was also responsible for moving funds from donors in the Gulf to Al-Qaeda leaders, according to the Pentagon.

The Syrian Observatory for Human Rights said al-Nasr was killed along with two other senior Al-Nusra members when an air strike hit their car.

In July, the Pentagon said it had taken out Muhsin al-Fadhli, another Khorasan Group leader, in a "kinetic strike" while he was traveling in a vehicle near the northwestern Syrian town of Sarmada.