At least two civilians were killed in Russian airstrikes on a former pumping station occupied by displaced people in rebel-held northwest Syria, an aid group operating there said on Wednesday.

The strikes took place on Tuesday night near Ain Shib, west of the city of Idlib, an AFP correspondent in the region said.

“Two men, civilians, were killed (…) and five other people were injured, among them a woman and two children,” Rami al-Dadal, who belongs to the White Helmets, a rescue organization, told the AFP correspondent.

According to the same source, one of the dead was 18 years old, the second was elderly.

Russia, the main ally of President Bashar al-Assad’s regime, which intervened militarily in Syria’s war in 2015, has in recent weeks been escalating its raids on Idlib province, the last major rebel stronghold in northwestern Syria, which is partly controlled by the jihadist organization Hayat Tahrir al-Sham (HTS), the former al-Qaeda arm in the country.

According to the Syrian Observatory for Human Rights, a non-governmental organization which is based in Britain and has a wide network of sources in war-torn Syria, the Russian strikes were aimed at “HTS military bases”. The NGO also spoke of two dead, injured and missing.

Other Russian airstrikes took place overnight on Tuesday-Wednesday in the city of Ariha, south of Idlib, the correspondent and the NGO said.

The last major enclave of the armed opposition includes, in addition to much of Idlib province, some parts of the neighboring provinces of Aleppo, Hama and Lattakia. About 3 million people live in this area, almost half of whom are internally displaced, who fled from other areas under the control of the anti-regime.

Hours before last night’s attacks, Russian airstrikes targeting a militant base in northern Idlib killed three HTS members and wounded seven other fighters and five civilians, according to the Syrian Observatory for Human Rights.

Yesterday Monday, always according to this NGO, 13 fighters were killed and others were wounded in strikes by the Russian Air Force near the city of Idlib. Previous strikes killed three people, all civilians and members of the same family, on August 5, as well as 13 people, including nine civilians, on June 25.