A senior minister in Bashar Assad’s government claimed on Tuesday that the Syrian air force had destroyed two of the three fighter jets in the Islamic State group's possession, Associated Press, or AP, reported Wednesday.

Omran al-Zoubi, a minister in Assad’s cabinet, reportedly said that Syrian jets had shot down two of the three planes as they returned to land at the al-Jarrah military airport, in territory captured by the Islamic State group, east of the Syrian city of Aleppo. He added that the militants had managed to hide the third plane and that the military is now searching for it. Al-Zoubi also claimed that the aircraft were old and that there was “no reason to worry about them,” AP reported.

The planes had been identified as MiG 21 or MiG 23 models by witnesses interviewed earlier by the Syrian Observatory for Human Rights, which had first reported the presence of the fighter jets under ISIS control on Friday.

However, Rami Abdel Rahman, director of the Observatory, reportedly said on Wednesday that he had no confirmation that the Syrian air force had destroyed the planes.

In recent days, the Syrian army has stepped up its military campaign against rebel groups in the country, according to media reports. A number of people have been killed in rebel-held areas in Quneitra, Deraa, the Damascus countryside, Hama, Idlib and Aleppo, since Sunday, the Observatory said, adding that more than 200 airstrikes were carried out by government forces in the last 36 hours.