The United States believes the two-month-old cessation of hostilities in Syria is still in place and "largely holding" despite an increase in violence and accusations of violations by rebels and the government.
State Department spokesman John Kirby said Tuesday the level of fighting remains below where it was before the truce went into effect at the end of February.
The U.N.'s envoy for Syria Staffan de Mistura described the increase in violence as "worrisome" in his latest assessment this week, but he also said the cease-fire is holding in many areas.
Kirby said Syrian forces were "most likely" responsible for airstrikes in two opposition-held towns in northwestern Syria that killed 44 civilians.
"The majority of the violations have been by the regime and we have reason to believe at this point that that was the case with this particular bombing," said Kirby.
The Syrian Observatory for Human Rights said Syrian warplanes carried out the strikes, the deadliest of which hit a vegetable market in the town of Maarat al-Numan Tuesday. The other airstrike happened in nearby Kafranbel.
The shelling followed fighting Monday in the coastal province of Latakia, the stronghold of President Bashar al-Assad’s minority Alawite sect, an offshoot of Shi'ite Islam.