BEIRUT - Suspected Russian airstrikes pounded villages on the edge of the last rebel enclave in northwestern Syria, sending thousands of civilians fleeing, activists reported Tuesday — scenes unseen in the area since a cease-fire three months ago.

The violence at the edge of Idlib province is the most serious breach of the cease-fire in place since early March, when an agreement between Turkey and Russia halted the Syrian government’s three-month air and ground campaign into rebel-held Idlib.

The Syria Response Coordination Group, a team of aid workers, said the military escalation displaced more than 5,800 civilians in the last 24 hours from areas in southern Idlib and western Hama countryside. Many of the displaced had only recently returned to their villages after the cease-fire, the group said.

On Monday, insurgents launched a limited offensive against government-held positions, briefly seizing a couple of villages. Government troops, backed by Russian air support, responded, repelling the insurgents but also widening their area of operations, targeting 10 villages, according to Mohamed Rasheed, a Syrian media activist documenting the offensive.

Rasheed reported airstrikes, believed to be carried out by Russia's air force, on a number of villages in southern Idlib. He said he documented 45 airstrikes since Monday.

The Britain-based Syrian Observatory for Human Rights recorded 15 airstrikes on Tuesday, also saying they were believed to be Russian. The Observatory and other local networks said at least one civilian was killed in Kansafra village.

Meanwhile, Syrian state media said government forces repelled an offensive by the insurgents, and that a soldier was killed.

Russia is a main backer of Syrian President Bashar Assad, while Turkey backs opposition fighters trying to remove him from power. Russia and Turkey have become the main power brokers in the war-torn country.

Rasheed said the insurgent offensive was led by the al-Qaida-linked Hayat Tahrir al-Sham, now the dominant group in the rebel-held northwest.

News from © The Associated Press, 2020