Iran on Monday vowed to respond to any "adventurism", its foreign ministry said, after the U.S. and Britain joined Israel in blaming Tehran for a deadly tanker attack, claims it denies.

The MT Mercer Street, managed by prominent Israeli billionaire Eyal Ofer, was attacked on Thursday off Oman.

Israel's key allies the United States and Britain joined it Sunday in blaming Iran for a deadly tanker attack off Oman, despite Tehran's denials, and Washington vowed an "appropriate response".

The U.S. and British statements came after Israeli Prime Minister Naftali Bennett said there was "evidence" linking Iran to the attack after the Islamic republic rejected its arch-foe's "baseless accusations".

Hamas leader Ismail Haniyeh has been re-elected unopposed, officials confirmed Monday, furthering his grip over the Palestinian Islamist group that controls the Gaza Strip after recent clashes with Israel.

In a statement, Hamas said that its electoral process had concluded with his reappointment as political chief after "tens of thousands" of members took part in the internal poll. 

Egypt's military said Sunday it has killed 89 suspected insurgents in operations in North Sinai, a region where an affiliate of the Islamic State group has been active for nearly a decade.

Israel's prime minister Sunday directly blamed Iran for a drone attack on an oil tanker off the coast of Oman that killed two people, making a veiled threat to retaliate as Tehran denied being involved in the assault.

The comments by Premier Naftali Bennett and Iranian Foreign Ministry spokesman Saeed Khatibzadeh come after the strike Thursday night on the oil tanker Mercer Street. The attack marked the first-known fatal attack after years of assaults on commercial shipping in the region linked to tensions with Iran over its tattered nuclear deal.

Israeli Prime Minister Naftali Bennett on Sunday denounced the painting of swastikas on a synagogue near Tel Aviv, calling it a "grave act of hatred".

The United States will help investigate a deadly attack on an oil tanker managed by a prominent Israeli billionaire, the State Department said.

Albania is repatriating five Albanian women and 14 children from Syria's troubled Al Hol camp who were related to Albanians who joined Islamist extremist groups fighting in Syria and Iraq, the country's prime minister said.

Albanian Prime Minister Edi Rama and Interior Minister Bledi Cuci were in Beirut meeting with Lebanese General Security chief Maj. Gen. Abass Ibrahim, who has played a key role in the repatriating efforts, together with intelligence services from other countries.

Iran's foreign ministry on Sunday rejected "baseless accusations" after Israel blamed its arch-foe for a deadly attack on an oil tanker off the coast of Oman.

Israel's foreign minister said he has ordered the nation's diplomats to push for U.N. action against Iran over a deadly attack on a ship managed by an Israeli billionaire.