Now that the eastern Ghouta rebels have surrendered, the area is under government control, and a team of global inspectors has so far been unable to reach it.
The War Media, the media wing of the Syrian army, said the shelling started against the terror-labeled militants in Yarmouk Camp.
Jarablus is shared between Turkish and Syrian opposition control.
Government warplanes targeted "the dens of terrorists from al-Nusra Front and Daesh in Hajar al-Aswad", a southern district of Damascus, state news agency SANA said on Thursday, referring to Syria's former al-Qaeda affiliate and using an Arabic acronym for ISIL.
Dumayr, in the Qalamoun mountains, is a short drive away from Douma, the site of the alleged April 7 chemical weapons attack.
The attack led to Theresa May, Donald Trump and Emmanuel Macron joining forces to take out three chemical weapons facilities in the country. The three countries said they held the Syrian government and its ally Russian Federation responsible for the attack.
Meanwhile, US Defense Secretary Jim Mattis has said that the Syrian government is responsible for delays in inspectors reaching sites of a suspected chemical weapons attack.
Stephane Dujarric told reporters at U.N. headquarters Thursday that "due to the volatility" of the situation on the ground in Douma the United Nations doesn't want "to telegraph" when a U.N. security team will return to Douma to check out whether conditions on the ground are safe for the inspectors to visit.
State Department spokeswoman Heather Nauert said USA officials "have credible information that indicates that Russian officials are working with the Syrian regime to deny and to delay these inspectors from gaining access to Duma".
Philip Issa is an Associated Press writer.
The Army of Islam, which controlled Douma at the time of the attack, surrendered the town to the government days later. It says the militants posed a threat to Iraq, without providing further details.
A war monitoring group, the Syrian Observatory for Human Rights, said there were also talks under way between Russian Federation and rebels for the insurgents to withdraw from an enclave in central Syria around the town of Rastan.