Clashes between Syrian rebels and Hizbullah on the Lebanese border have killed at least four fighters, a security official said Sunday.

The fighting erupted on Saturday in an undemarcated area of the frontier between Qalamun in Syria and Arsal in Lebanon’s Bekaa region, the Lebanese official told Agence France Presse, speaking on condition of anonymity.

A rocket fired from Syria hit the Israeli-occupied sector of the Golan Heights on Sunday, falling on open ground and causing no casualties, an Israeli army spokeswoman told Agence France Presse.

"The assumption is that it was not a stray," she said, although there was no immediate report of Israeli retaliation.

Hamas' armed wing, the Ezzeddine al-Qassam Brigades, announced firing rockets from Gaza at Tel Aviv in central Israel, its suburb Rishon LeZion and the northern city of Haifa on Sunday afternoon.

“Al-Qassam Brigades have shelled Haifa with an R160 rocket, Tel Aviv with 3 M75 rockets and Rishon LeZion with a Fajr-5 rocket,” the pan-Arab al-Mayadeen television reported earlier.

Hizbullah has sent reinforcements to several cities in Reef Damascus amid reports of a possible attack on the region by the Syrian opposition's fighters, the Syrian Observatory for Human Rights said on Saturday.

"Hizbullah continues to send reinforcements to areas in al-Qalamoun plains and to the surroundings of al-Zabadani (50 kilometers northwest of Damascus),” the Observer announced in a statement, noting that this might be part of a plan for an attack on the region by the Syrian regime's forces aided by Hizbullah.

Several rockets were fired on northern Israel from the outskirts of the town of Mari in Hasbaya on Friday morning, drawing retaliatory Israeli artillery fire, the Lebanese army and the state-run National News Agency said.

The Internal Security Forces Intelligence Bureau later arrested a suspect linked to the attack.

The U.S. Treasury Department on Thursday sanctioned a network of firms and individuals in Lebanon, the UAE and China for allegedly procuring sophisticated military equipment for Hizbullah, including materials for aerial drones.

“As the Treasury Department announced today, the United States targeted a key Hizbullah procurement network by designating brothers Kamel Mohamad Amhaz and Issam Mohamad Amhaz; their business, Stars Group Holding, which is based in Beirut and has subsidiaries in China and the UAE; and certain managers and individuals who supported their illicit activities,” the U.S. State Department said in a statement.

Progressive Socialist Party leader MP Walid Jumblat stressed on Wednesday that Lebanon cannot have a confrontational presidential nominee, urging an agreement on a consensual candidate to end the deadlock in the country's top post.

"I don't see an end to the (presidential) crisis because both nominees are confrontational. They have to understand that neither of them can be a confrontational candidate,” Jumblat said in an interview on Al-Jazeera television on Wednesday evening.

Israeli warplanes pounded Gaza Wednesday, killing at least 30 people in a major new confrontation with Palestinian militants, as Hamas flexed its firepower and sent thousands running for shelters across Israel.

As the death toll from Israel's two-day Operation Protective Edge reached 57, Palestinian President Mahmoud Abbas accused Israel of committing "genocide" in Gaza.

The Syndicate Coordination Committee vowed on Saturday to continue boycotting the correction of the official exams until the adoption of the contentious new wage scale.

"We will continue boycotting the correction of exams until the new wage scale gets adopted and all sectors secure their employment rights without any exception,” the SCC said after a meeting.

Palestinian factions in Lebanon agreed on Saturday to start the deployment of Palestinian security forces in the southern Ain el-Hilweh refugee camp as of Tuesday afternoon.

The decision was announced after an expanded meeting held at the headquarters of the Palestinian National Security Forces in the camp, with the participation of representatives of all Islamic and Palestinian factions in Lebanon.