BEIRUT — Syrian government and Russian warplanes bombed the southern edge of Idlib Province on Saturday, ratcheting up military pressure on the densely populated rebel-held bastion.

The bombings came a day after a summit meeting in Tehran where the Syrian government’s ally Russia rejected Turkey’s call for a cease-fire while Iran, another Syria backer, called for a military push to crush the rebels and drive out American forces.

More than 60 airstrikes, including indiscriminate barrel bombs dropped from helicopters, killed at least four civilians in the area, according to rescue workers and the Syrian Observatory for Human Rights, a monitoring group based in Britain.

The state-run Al-Ikhbariya television station said the government was retaliating against shelling Friday night from rebel-held areas on a government-held town in Hama Province, south of Idlib. Nine civilians were killed in the shelling, state media reported. The state news agency SANA said government forces have shelled “terrorist” posts in northern Hama.