An airstrike has killed a top Al Qaeda commander and two other fighters in Syria, activists said Saturday, but it was not immediately clear whether it was carried out by the U.S.-led coalition or Russian warplanes.

The Britain-based Syrian Observatory for Human Rights said Abdul Mohsen Abdallah Ibrahim al-Charekh, a Saudi better known as Sanafi al-Nasr, was killed Thursday in an airstrike near the northern Syrian town of Dana, along with another Saudi and a Moroccan member of Al Qaeda's local affiliate, known as the Nusra Front.

Russian warplanes have been carrying out airstrikes in Syria since Sept. 30. A U.S.-led coalition has been targeting the Nusra Front and the Islamic State group for more than a year.

The Observatory's chief Rami Abdurrahman said it was not clear if al-Charekh was killed by U.S. or Russian warplanes. The Observatory, which relies on a network of activists inside Syria, said an Egyptian commander escaped the bombing. It said all four men had been dispatched to Syria by Al Qaeda leader Ayman al-Zawahri.

Jihadi activists on social media say al-Charekh was killed by a U.S. drone strike.

A U.S. official said an American drone targeted and struck al-Charekh but the U.S. was waiting for confirmation that he was actually killed in the attack. The official was not authorized to discuss the strike publicly so spoke on condition of anonymity.

Al-Charekh, the alleged leader of Al Qaeda's operations in Syria, was one of six men that the U.N. Security Council imposed sanctions on last year. He was 49th on a list of 85 most-wanted militants by Saudi Arabia who are outside the kingdom. The list, issued in 2009, includes 83 Saudis and two Yemenis.

"America is offering its services to the Safawi (Iranian) project in the region by removing every brain who confronts this project," wrote prominent Lebanese jihadi cleric Sirajeddine Zuraiqat on Twitter. Zuraiqat is believed to be in Syria and is wanted in his home country.

The U.S. killed top Al Qaeda official Muhsin al-Fadhli in an airstrike three months ago. Some Arab press reports suggested that al-Charekh was a member of the Khorasan group, a secretive cell of Al Qaeda operatives who U.S. officials say were sent from Pakistan to Syria to plot attacks against the West.

The Nusra Front's leader, Abu Mohammed al-Golani, has denied the existence of the Khorasan group.

In Moscow, Maj. Gen. Igoro Konashenkov said Russian aircraft conducted 36 sorties over the past 24 hours, striking a total of 49 positions. He said the airstrikes were in the province of Hama, Idlib, Latakia, Damascus and Aleppo.

Konashenkov said one of the targets was a building on the outskirts of the town of Salma in the coastal province of Latakia where foreign instructors prepared militants.

Syria's state news agency, SANA, said troops carried out operations in Salma and nearby areas killing and wounding at least 300 fighters. "Several vehicles and hideouts were destroyed," SANA said.

Salma is in the mountains of Latakia province that is a stronghold of President Bashar Assad and is predominantly inhabited by members of his minority Alawite sect.

Since Russian airstrikes began two weeks ago, Syrian troops have been on the offensive on several fronts around the country.

The Observatory said government forces captured the villages of Wadihi, Sabqiyeh and Shgheidleh in Aleppo province under the cover of airstrikes. It added that fighting on the southern edge of Aleppo province killed 17 militants and eight troops and pro-government gunmen.