Deaths have been reported in an Israeli air strike on a car in Syria, according to Syrian state media and activists.
Sources on all sides, however, disagreed over the identity of those killed in Friday's attack on the Syrian side of the Golan Heights.
It was the second straight day of Israeli strikes inside Syria.
Syrian state TV reported that a car was targeted near the village of Quneitra and that five civilians were killed.
However, the Syrian Observatory for Human Rights said they were all Syrian soldiers or served in paramilitary units loyal to Syrian President Bashar al-Assad.
The Syrian army said one of its soldiers was killed in one of the Israeli raids.
Israeli army officials said four Palestinian members of the Islamic Jihad group, supported by Iran, were killed in the strike.
But Islamic Jihad said those killed were not among its own.
"These are all lies ... Islamic Jihad has no armed presence outside of Palestine," Dawoud Shehab, a group spokesman, told Reuters news agency.
The Israeli army said it carried out the air strike in retaliation for rocket strikes into northern Israel on Thursday, which it said were fired from Syria.
"The IDF hit both the cell that carried out the firing and the Syrian forces that made it possible," Benjamin Netanyahu, Israeli prime minister, said in a statement, referring to the country's army by its acronym.
"We have no intention to escalate events," he said, but added that Israel would take action against any attackers.
Netanyahu said an Iranian commander directed the rocket attacks on Thursday, which caused no injuries.
The Britain-based Syrian Observatory said it had counted seven people killed in Israeli air strikes on Thursday and Friday.
ISIL destroys ancient monastery in central Syria
Previous cross-border fire has frequently been attributed to spillover from fighting inside Syria and to fighters holding ground close to the Israeli-held sector of the Golan Heights.
The Lebanese Shia group Hezbollah, which is allied to the Syrian government, was the target of a deadly Israeli attack in January in which six of its fighters and an Iranian general were killed on the Syrian side of the border.
Several days later Hezbollah retaliated, killing two Israeli soldiers.
Elsewhere in Syria, 15 people have been killed in government air raids over eastern Aleppo.
Medical sources have told Al Jazeera the planes targeted Al Bab, a town in the Aleppo countryside that has been under the control of the Islamic State of Iraq and the Levant (ISIL) group and is a regular target.
But opposition activists say the Syrian government is deliberately targeting civilian neighbourhoods.