There was no immediate comment from Syrian activists who monitor the conflict on the fate of Abu Mohammed al-Golani, leader of the al-Qaida-linked Levant Liberation Committee. Russia has been waging an air campaign in support of Syrian President Bashar Assad's forces since 2015, helping them to make major advances against the Islamic State group, al-Qaida-linked insurgents and mainstream rebels.
Syrian troops are currently closing in on the eastern city of Mayadeen, one of the last major IS strongholds in the country. The Britain-based Syrian Observatory for Human Rights said Syrian troops and allied militiamen have advanced to about 10 kilometers (six miles) north of Mayadeen. The activist-operated Deir Ezzor24 says dozens of rockets and barrel bombs fell on Mayadeen and surrounding villages on Wednesday.
The Observatory said at least 20 people were killed in airstrikes on a village north of Mayadeen, while Deir Ezzor24 said at least 15 were killed. Tens of thousands of civilians have fled Mayadeen and the surrounding areas in the past week.
The Observatory said the government advance has been preceded by a barrage of airstrikes, counting over 1,000 since Friday. Mayadeen has become the main hub for Islamic State militants, including the group's leaders, as its former strongholds in Raqqa, Deir el-Zour and Mosul have come under attack.
U.S-backed Syrian forces and the Russia-backed Syrian military are in a race for control of territory in eastern Syria as they both battle the extremist group. Al-Golani's Levant Liberation Committee controls the northwestern Idlib province, on the other side of the country. Maj. Gen. Igor Konashenkov, the Russian Defense Ministry spokesman, announced the wounding of the militant leader.
As with other top insurgent leaders, al-Golani's death has been falsely reported in the past. Konashenkov said Russia carried out the airstrikes at an undisclosed location in Syria on Tuesday after receiving intelligence about an upcoming high-level meeting of the group's leaders. He said 50 other militants who were securing the gathering were also killed.
Rami Abdurrahman, the head of the Observatory, said Wednesday he had no information about al-Golani. But the Observatory did report that a former air base now controlled by the Levant Liberation Committee in Idlib was struck by 23 airstrikes on Tuesday. The Observatory said no ambulances were allowed into the area after the attacks.
The al-Qaida-linked group denied the Russian report in a statement issued later Wednesday. It said al-Golani is in excellent health and is carrying on with his tasks normally. The statement was published on the group's Telegram channel.
Moscow blamed the al-Qaida-linked group for an attack on Russian military police near Idlib last month. Three Russian troops were wounded after the militants encircled 29 Russian military officers for several hours during an insurgent offensive. The Russian troops repelled the attack with the help of local tribes.
Idlib has come under intense aerial attack since then.
Associated Press writer Sarah El Deeb in Beirut contributed to this report.