RAMALLAH, West Bank — The Israeli military launched a second round of airstrikes in Syria on Friday morning, killing all of the passengers traveling in a vehicle and intensifying the most serious conflict in the area in months.
The Israeli military said it was pursuing militants who had fired at Israeli-controlled areas on Thursday, saying in a statement that the air force had “targeted part of the terror cell responsible for the rocket fire at northern Israel on Thursday” but providing no further information.
Sana, the official Syrian news agency, said an Israeli drone strike hit a civilian vehicle near a marketplace in Al Koum, a village in the Quneitra area on the Syrian-controlled side of the Golan Heights.
Israel repeated its claim on Friday that Iran was to blame for the rocket fire, seeking to use the attack as further evidence that the United States Congress should reject the nuclear deal reached last month between world powers and Iran.
Specifically, Israeli officials said an Iranian commander had supervised militants of the Palestinian group Islamic Jihad and accused the organization of firing four rockets toward the Israeli-controlled Golan Heights and Upper Galilee on Thursday. There were no casualties in that attack.
The Israeli news media reported that its airstrike had hit a military vehicle and killed the passengers, either four or five people, less than 10 miles from the Israeli-controlled frontier.
That account was supported by the Syrian Observatory for Human Rights, a monitoring group in Britain, which said that the vehicle had been carrying five progovernment militia fighters who belonged to a group known as the National Defense Forces, but provided no further information.
In statements made to the Palestinian news media, Daoud Shihab, the chief spokesman for Islamic Jihad, denied any involvement in the rocket attack. Mr. Shihab said the militant wing of Islamic Jihad operated “inside occupied Palestine” — a reference to Israel and the Palestinian Territories. There was no immediate comment from Iranian officials.
After the airstrike, Prime Minister Benjamin Netanyahu said Israel had “no intention of escalating events, but our policy remains unchanged.”
“Those countries that hasten to embrace Iran must realize that it was an Iranian commander who provided protection and direction for the cell that shot at Israel,” he said.
Dore Gold, the director general of the Israeli Foreign Ministry, said in a telephone interview that “it is untenable that Iran can argue it is in a diplomatic process in the West, while its forces continue to wage wars of subversion and terror across the Middle East.”
“Iran derives legitimacy from the nuclear agreement,” Mr. Gold said. “There’s a problem here: almost like an inconsistency between Iran’s stated position of being a diplomatic partner and the continuing warfare.”
After the rocket fire on Thursday, Israeli aircraft conducted retaliatory strikes against more than a dozen Syrian military posts. The Observatory said on Friday that two soldiers had been killed in those strikes.
An Israeli military official said that the rocket fire on Thursday had been “clearly intentional” and not errant fire that had come across Israeli-held territory.
In a sign of protest lodged with the world powers that negotiated the nuclear agreement, Israeli officials said in a statement that they had “credible information” that the attack was carried out by Islamic Jihad operatives.
The statement said that the attack was “facilitated and directed” by Saeed Izaadhi, describing him as an Iranian operative “who heads the Palestinian unit” of the Quds Force of the Revolutionary Guards in Iran.
“We know that the situation along the border won’t be what it was in the past,” Eli Malka, the Golan Regional Council chairman, said in a radio interview after the strikes.
“This is now a hostile border,” Mr. Malka said in the interview. “We realize that things have changed, and we have prepared. We’ve prepared in many ways. In fortifications, in building the fortitude of the residents, in improving the interface between us and the army.”