The United States' top diplomat warned Iran on Sunday that time is running out on nuclear negotiations between the Islamic republic and world powers.

"This is not an endless process. ... You can't just talk for the sake of talking," Secretary of State John Kerry told a news conference in Istanbul.

Israel said it was time for world powers to adopt a "firmer stand" with Iran on its controversial nuclear program after their latest round of negotiations closed on Saturday without any breakthrough.

"It is time for the world to take a firmer stand and tell the Iranians in no uncertain terms that the masquerade of negotiations is about to end," Strategic Affairs and Intelligence Minister Yuval Steinitz said.

Iran and world powers Saturday meet for a second and final day of a new round of talks aimed at breaking a decade-old deadlock over the Islamic state's disputed nuclear program, with time slowly running out on a solution.

The two sides held a tense day of negotiation in the Kazakh city of Almaty on Friday that ended with only an agreement to meet again.

A service truck crashed into a passenger lounge of Jeddah international airport in Saudi Arabia, killing two Iranian pilgrims and injuring four others, reports said on Friday.

The truck, driven by a Nepalese man, careened through the glass panes of the King Abdulaziz International Airport terminal on Thursday, the reports said, citing the Saudi Civil Aviation Authority.

EU foreign policy chief Catherine Ashton said Wednesday she was cautiously optimistic over the outcome of talks this week between Iran and world powers on Tehran's nuclear drive.

Officials from the so-called P5+1 grouping meet negotiators from Iran in Kazakhstan on Friday, hoping for a response to a revised offer that would ease some sanctions in return for concessions over its uranium enrichment activities.

A Bahraini accused of spying for Iran's elite Revolutionary Guards unit has had his 10-year jail sentence confirmed by a court of appeal, the state news agency BNA news agency reported.

The sentence, passed in July 2011 by a lower court, was confirmed on Sunday by the Court of Appeal in Manama, the report said.

The first direct flight connecting Egypt and Iran in more than 30 years took off from Cairo International Airport on Saturday, airport officials told Agence France Presse.

The Air Memphis plane, chartered by Egyptian businessman Ramy Lakah, is the first direct flight between the capitals since the two countries severed ties after Iran's 1979 Islamic revolution.

A top diplomat on Friday condemned the move by the Gulf state of Qatar to let Syria's opposition open an "embassy" in Doha, calling the decision "hasty and irrational," Iran's official IRNA news agency reported.

"Qatar's theatrical act in giving the Syrian embassy to a group which is unelected is both hasty and irrational," the deputy foreign minister in charge of Arab and African affairs, Hossein Amir Abdollahian, was quoted as saying.

Iran, North Korea and Syria blocked adoption of a U.N. treaty that would regulate the multibillion-dollar international arms trade for the first time, saying it fails to ban sales to terrorists, but other countries refused to let the treaty die.

The treaty's adoption required agreement by all 193 U.N. member states, but some countries said Thursday they would ask Secretary-General Ban Ki-moon to bring the final draft before the General Assembly for adoption by vote as soon as possible. Observers said that could be as soon as Tuesday.

Iran's foreign ministry has strongly protested against a Saudi accusation that it was directly linked to an alleged spy cell busted last week in the kingdom, Iranian media reported on Wednesday.

Saudi Arabia's interior ministry said on Tuesday that the cell it dismantled last week had "direct links" to Iran's intelligence services.