An Israeli air strike on a car in the Gaza Strip killed two Palestinians Friday, medics said, hours after a bomb exploded near troops manning Israel's security fence.

The violence comes a day after Israel accused two men it said belong to Hamas of kidnapping three Israeli teenagers in the occupied West Bank a fortnight ago.

U.S. Secretary of State John Kerry arrived in Saudi Arabia Friday to meet the Syrian opposition as Washington unveiled plans to provide some $500 million in arms and training to the rebels.

The top U.S. diplomat, who landed in the Red Sea city of Jeddah in the afternoon, will also meet Saudi King Abdullah, a day after hosting urgent talks in Paris with the Saudi, Jordanian and UAE foreign ministers to discuss the widening crisis in Iraq and Syria.

Iraqi Kurdish leader Massud Barzani said Friday there was no going back on autonomous Kurdish rule in oil city Kirkuk and other towns now defended against Sunni militants by Kurdish fighters.

"Now, this (issue) ... is achieved," he said, referring to a constitutional article meant to address the Kurds' decades-old ambition to incorporate the territory in their autonomous region in the north over the objections of successive governments in Baghdad.

Iraqi forces fought for a strategically located university campus outside Tikrit Friday and bombarded the city in an effort to retake it from Sunni Arab insurgents.

The military operation came after Prime Minister Nuri al-Maliki conceded that political measures will also be needed to defeat the jihadist-led offensive that has killed nearly 1,100 people overrun major parts of five provinces.

Italy has advised its citizens not to invest in Israeli settlements built on occupied Palestinian land, just days after France issued the same warning, Italian media reported Friday.

Foreign Minister Federico Mogherini cautioned Italians "not to get involved in financial activity and investments" in settlements in the occupied West Bank, the Gaza Strip and East Jerusalem, according to La Stampa daily.

Syria's opposition government sacked the military command of the rebel Free Syrian Army late Thursday over corruption allegations, as the White House asked lawmakers for $500 million for moderate insurgents.

A statement by the opposition government said its chief Ahmad Tohme "decided to disband the Supreme Military Council and refer its members to the government's financial and administration committee for investigation".

Five Palestinians in the Gaza Strip were wounded Friday by Israeli tank shells fired in response to the detonation of a border bomb, Palestinian medics and the Israeli army said.

A spokesman for Gaza's health services, Ashraf al-Qudra, told Agence France Presse the five were wounded after the tanks targeted "two mosque minarets" east of Khan Yunis in southern Gaza.

Kuwaiti voters elected pro-government candidates to replace five opposition lawmakers who resigned two months ago in by-elections that saw one of the lowest turnouts in the emirate's history.

The results will boost the grip of the government on the 50-seat parliament where it already enjoyed a comfortable majority. 

Human Rights Watch said Thursday that fighters inspired by al-Qaida had executed Iraqi soldiers en masse this month in Tikrit.

In mid-June, militants from the Islamic State of Iraq and the Levant (ISIL) posted photos online of what they claimed to be the bodies of dozens of captured security forces members they had executed.

Dozens of Chinese workers have been relocated from strife-torn northern Iraq, state media said Friday, with an additional 1,200 set to depart in the coming days.

More than 50 China Machinery Engineering Corp (CMEC) workers arrived in Baghdad by helicopter from northern Iraq on Wednesday night, the state-run China Daily newspaper reported.