There are some in Tehran convinced a final nuclear deal between Iran and world powers has already been sealed. Others are adamant there will never be a pact.

But as uncertainty persists over talks aimed at ending the 12-year standoff on Iran's disputed atomic program, hurdles to an agreement are stacking up.

Chairman of Iranian Parliament's National Security and Foreign Policy Committee Alaeddin Boroujerdi concluded on Saturday a visit to Lebanon during which he met with various Lebanese officials, including Speaker Nabih Berri, Prime Minister Tammam Salam, and Hizbullah chief Sayyed Hassan Nasrallah.

Salam had hoped during his talks with the Iranian official that Tehran would exert efforts that would help end the presidential deadlock in Lebanon, reported the pan-Arab daily al-Hayat on Sunday.

Director of the Department of the Middle East and North Africa at the French Foreign Ministry Jean-François Girault is expected to return to Beirut on Monday to continue his efforts to achieve a breakthrough in the ongoing deadlock over the presidential elections, reported the daily An Nahar on Sunday.

Observers ruled out the possibility that the French official would be able to create a breakthrough in his talks with local figures.

The U.S. Senate Banking Committee approved a controversial measure Thursday that would ratchet up sanctions on Iran, a legislative weapon Congress could wield after March if international nuclear talks hit an impasse.

Senators voted 18 to 4 to advance the so-called Kirk-Menendez bill, which is steadfastly opposed by the White House.

Iran appointed a new U.N. ambassador Wednesday following Washington's refusal to grant a U.S. visa to a previous nominee over the 1979 embassy hostage crisis, state news agency IRNA said.

"Gholam-Ali Khoshroo has been chosen as the Islamic republic's permanent ambassador to the United Nations in New York," the foreign ministry said, quoted by IRNA.

Iranian officials will meet with European members of the P5+1 group in Istanbul on Thursday under the ongoing diplomatic effort to secure a deal over Tehran's disputed nuclear program.

The meeting with British, French and German diplomats was announced by Iran's foreign ministry spokeswoman Marzieh Afkham during a weekly press briefing in Tehran.

Bahraini Shiite opposition chief Sheikh Ali Salman rejected charges that he tried to overthrow the country's Sunni regime, as his trial opened Wednesday, a judicial source said.

Hours later, hundreds of supporters gathered outside Salman's home in a Manama suburb and clashed with riot police, who used tear gas to disperse them, witnesses said.

U.S. President Barack Obama won breathing room Tuesday for his nuclear dialogue with Iran, as legislation calling for strict new sanctions against the Islamic republic lost some crucial support in Congress.

Senator Robert Menendez announced that he and several fellow Democrats had assured Obama they would not vote in support of new sanctions prior to March 24, shortly before a negotiations target date.

Iran's parliament has started to draft a law that would allow the country's nuclear scientists to intensify their uranium enrichment, a step that could complicate ongoing talks with world powers.

The move, announced Saturday by parliament's National Security and Foreign Policy Committee, comes after U.S. lawmakers said they were planning legislation that could place new sanctions on Iran.

World leaders converged on Saudi Arabia Saturday to offer condolences following the death of King Abdullah, with U.S. President Barack Obama cutting short a trip to India to pay respects.

Obama will travel to Riyadh on Tuesday to meet new King Salman, the White House said.