The UK-based Syrian Observatory for Human Rights said Israeli strikes on a military base run by Iranian-backed Lebanese Hezbollah caused the series of blasts.
Syrian regime forces said on Friday a series of blasts at an ammunition depot east of Homs city led to casualties but was not caused by an attack as earlier announced, but a war monitor said it was the result of an Israeli strike.
The forces said in a statement released on state TV there were civilian losses without elaborating on details.
The UK-based Syrian Observatory for Human Rights said Israeli strikes on a military base run by Iranian-backed Lebanese Hezbollah, which lies on the Homs-Palmyra road, caused the series of blasts.
The war monitor echoed reports by residents of the area that the sounds of the explosions were heard across Homs city.
The attack follows overnight strikes by Israeli helicopters from the Israeli occupied Golan Heights on Iranian bases in southern Syria, according to the monitor and intelligence sources.
The Syrian regime announced after midnight Israel had attacked, but did not elaborate on the targets in Quneitra province. It rarely says Iranian bases are hit.
Israel in recent years has launched hundreds of attacks on Iranian-backed militias and their bases in Syria, where they have a large presence across the country.
Israel was stepping up its raids in Syria at a time when world attention and the region, including Syria, was distracted with tackling the new coronavirus, a regional intelligence source said.