A U.N. envoy called for an extension of a five-day humanitarian ceasefire in Yemen due to expire later Sunday as the Huthi Shiite rebels boycotted political talks in Riyadh.

The appeal followed clashes between rebels and pro-government forces across south Yemen on Saturday despite the truce, which has largely held since starting at 11:00 pm (2000 GMT) Tuesday.

President Barack Obama tried to reassure America's Gulf allies Thursday that engaging with Iran would not come at their expense, at a Camp David summit that proved short on concrete outcomes.

Pledging to counter external threats to Gulf states amid Iran's growing role in the region, Obama said his security commitment to the decades-old allies was "ironclad."  

The Israeli parliament late Thursday narrowly approved Prime Minister Benjamin Netanyahu's new government as the United States insisted the Jewish state must forge a deal with the Palestinians for its own good.

The new administration marks a shift to the right and looks likely to complicate Netanyahu's fraught relationships with the Palestinians and with U.S. President Barack Obama.

Iranian Revolutionary Guard forces fired warning shots at a Singapore-flagged commercial ship in the Gulf on Thursday, before vessels from the United Arab Emirates came to the ship's aid, U.S. officials said.

The incident reflects rising tensions in the Gulf, fueled in part by the conflict in Yemen that pits Iranian-backed Shiite rebels against pro-government forces supported by a Saudi-led coalition of Sunni Arab states.

Yemen's government in exile said Thursday it was recalling the head of its embassy in Iran, accusing Tehran of "interference in our affairs and support for the Huthis" rebelling against authorities.

"The legitimate government of Yemen is recalling charge d'affaires Abdullah al-Sirri," a statement from the press office of President Abedrabbo Mansour Hadi said.

Iran said Thursday it had coordinated with the United Nations for the docking of an aid ship in Yemen, after calls from the Pentagon for it to divert to a U.N. hub in Djibouti.

The sending of the Iranian ship sparked a war of words with Washington and with Yemen's exiled government, which said measures would be taken if the vessel entered the country's waters.

Somalia's Al-Shebab Islamist militants have captured an Iranian fishing boat and its crew after it was forced to put into port due to mechanical failure, Iran's Fisheries Organization said Thursday.

"The 14 crew of the vessel are now in captivity and some of the Al-Shebab militants are on board" the privately-owned boat, fisheries chief Hassan Salehi said, quoted on state television's website.

U.S. President Barack Obama hailed America's "extraordinary friendship" with Saudi Arabia on Wednesday, as he hosted skeptical Gulf leaders at the White House for a summit beset by disagreements and royal no-shows.

Describing "an extraordinary friendship and relationship that dates back to (U.S. president) Franklin Roosevelt and King Faisal," in the 1940s, Obama heaped praise on two powerful Saudi princes in the Oval Office.

Syria's security services chief Ali Mamluk attended a meeting between President Bashar Assad and an Iranian official on Wednesday, after a newspaper claimed he was under house arrest for plotting a coup.

Mamluk's presence at the meeting, which was reported by the official news agency SANA, came after Britain's Telegraph newspaper said the top regime official had been sidelined.

A senior Iranian commander warned the United States that a "fire might start" over an aid ship bound for Yemen on Wednesday after the Pentagon urged it to change course.

Brigadier General Masoud Jazayeri said it was Iran's right to deliver relief supplies to Yemen as a humanitarian ceasefire takes hold and rejected Washington's request that aid be taken instead to a United Nations hub to allay worries the cargo might be military.