The Pentagon said Tuesday that there are some Shiite fighters at an Iraqi military base where Washington just sent 450 reinforcements, but they were not working with U.S. forces, underscoring concerns over links with the sectarian fighters.

Pentagon spokesman Colonel Steve Warren said that while there is a "small group" of Shiite fighters at the Taqaddum base, there numbered only in the lower double digits, did not form full units and did not interact with U.S. forces. 

A top Iranian official, in an unusual declaration Saturday, said there remains no trust between Tehran and world powers and either side could yet abandon a nuclear deal after signing.

In comments that laid bare a paradox of long-running negotiations between Iran and the West, Deputy Foreign Minister Abbas Araghchi said an agreement -- due by June 30 -- was nearing despite neither side trusting the other.

An American among several believed held by Huthis in Yemen was freed and receiving treatment Tuesday in neighboring Oman, which has been hosting talks between Washington and the Iran-backed Shiite rebels.

A diplomat in Muscat said the talks between the Americans and the Huthis were aimed at promoting a proposed peace conference in Geneva, which the United Nations has so far failed to persuade the warring parties to attend.

A delegation from the Afghan Taliban's Qatar-based political office is in Tehran for talks, Iranian media reported Tuesday.

The visitors, headed by Tayyab Agha, head of the political bureau, met Iranian security officials and discussed regional issues, "particularly developments in the Islamic world," Tasnim news agency said.

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."  

In an unusual move by Tehran's mayor, hundreds of copies of famous artworks — both of world masters and Iranian artists — have been plastered on some 1,500 billboards across the city, transforming the Iranian capital into a gigantic, open-air exhibition.

The 10-day project, which ends Friday, has stirred both appreciation and criticism. But whether people like it or not, the message is simple, according to Ehsun Fathipour.

Iran is determined to end the "manufactured crisis" over its nuclear program and drafting of a final deal with world powers, though hard, is progressing, Foreign Minister Mohammad Javad Zarif said Monday.

The remarks, on Zarif's official Twitter account, came two days after U.S. Secretary of State John Kerry denounced what he said was "hysteria" from opponents of an agreement, which is due by June 30.

Iran and major powers held a second day of talks Thursday seeking to finalize a historic deal that would make any attempt by Tehran to make a nuclear weapon extremely difficult and easily detectable.

Meeting in Vienna, Iran and the five permanent members of the U.N. Security Council plus Germany want to turn a framework accord reached in Switzerland on April 2 into a full agreement by June 30.

Speaker Nabih Berri has canceled the meeting of the Arab Inter-parliamentary Union (AIPU) that was set to be held in Beirut end of April after he was informed by Saudi Arabia that it would not attend the talks, al-Joumhouria daily reported on Thursday.

Berri informed Arab parliaments that “the conference has been canceled for non-Lebanese reasons,” said al-Joumhouria.

Iran and major powers on Wednesday began the difficult process of finalizing by June 30 a historic deal putting an Iranian nuclear bomb out of reach, three weeks after agreeing the main outlines.

Following a negotiating marathon in Switzerland, Iran agreed on April 2 to what U.S. President Barack Obama called a "historic understanding... which, if fully implemented, will prevent (Iran) from obtaining a nuclear weapon."