TEHRAN // Iran's new caretaker foreign minister, Ali Akbar Salehi, is regarded as an urbane, moderate and open-minded technocrat by western officials and academics who have met him in his capacity as his country's top nuclear official, a post he still holds.
One described him as "a man of peace" who seemed pained and baffled by the "unremitting" hostility of hawkish American neo-conservatives to the Islamic Republic.
Mr Salehi, 61, spent five years studying in the US in the 1970s and is said to be in favour of resolving Iran's nuclear dispute. But he insists on his country's right to pursue peaceful nuclear technology and not to make concessions.
"He was always a very pleasant and amenable person to deal with, a good functionary and civil servant," said a former European diplomat in Tehran. "He was somebody who could stick to his positions but was at the same time good at communicating with others."
Mr Salehi, however, is unlikely to have much room to manoeuvre because the framework and tenor of Iran's foreign policy are set by the supreme leader, Ayatollah Ali Khamenei.
But foreign envoys hope that their contacts with Iran's foreign ministry will now be more fruitful. Open bickering in recent months between the president, Mahmoud Ahmadinejad, and Manouchehr Mottaki, the long-serving foreign minister he sacked without explanation on Monday, made it confusing and difficult for diplomats.
The big decisions were made by players whom foreign envoys did not talk to. On the nuclear question, western diplomats are likely to find Mr Salehi a better person to approach than Mr Mottaki. Unlike his predecessor, Mr Salehi is familiar with both the technical and political aspects of the dispute.
Gary Sick, an Iran expert at Columbia University in New York, said: "You could hardly ask for a better representative," if the nuclear issue becomes the focus of talks that Iran is due to hold with world powers next month.
"He's a nuclear physicist who has had very extensive, deep and long-lasting involvement in Iran's nuclear programme at all levels," Mr Sick added in a telephone interview. "And his English is perfect."
As head of Iran's Atomic Energy Agency, a post he assumed in July 2009, Mr Salehi has spearheaded his country's nuclear drive and presided over the official launch of its first atomic power plant at Bushehr in August.
From 1997 to 2005, Mr Salehi was the international face of Tehran's nuclear programme as his country's ambassador to the UN's International Atomic Energy Agency. While there, he earned respect among foreign diplomats, many of whom harboured suspicions about Tehran's true nuclear ambitions but valued his professionalism.
Mr Salehi, a father of three, is fond of reminiscing about his student days in the United States, those who know him say. He graduated with a doctorate in nuclear engineering from the Massachusetts Institute of Technology in 1977, two years before Iran's Islamic Revolution.
He is also fluent in Arabic. He was born in 1949 in Karbala, Iraq and moved to Iran at the age of nine. He later attended the American University of Beirut, graduating in mechanical engineering.
That background could help smooth fraught relations with the Arab world. WikiLeaks has revealed the depth of mistrust among Sunni Arab leaders of Shiite Iran - and their fear of Tehran's nuclear ambitions.
It is far from clear whether Mr Ahmadinejad intends to make Mr Salehi's appointment permanent. Some believe the president chose him as a stopgap, knowing that Mr Salehi would be acceptable to Ayatollah Khamenei, and so ease his way to sacking Mr Mottaki, who was close to Mr Ahmadinejad's conservative rivals.
Scott Lucas, an Iran expert at Birmingham University in England, said: "Salehi is not an Ahmadinejad loyalist. He's a technocrat who's respected for being very capable but he doesn't play political loyalties within the regime."
It also remains to be seen how Mr Salehi will cope with the president's attempts to run his own "parallel" foreign ministry. Mr Ahmadinejad has appointed diplomatically inexperienced "presidential" envoys to various regions of the world, sidelining the foreign ministry, a move that infuriated Mr Mottaki.
The president's conservative rivals have accused him of surrounding himself with often inept cronies as he attempts to monopolise power in the presidency. Many analysts suspect Mr Ahmadinejad will now manoeuvre to install a hardline ally as his permanent foreign minister.
An analyst in Tehran, who declined to be identified because of the sensitivity of the subject, said: "Ahmadinejad's apocalyptic ideology … requires him to spread the word of Islam and his brand of Shiism outside the borders of Iran, so he needs to have one of his own men as foreign minister."
That man, Iran experts suspect, is Mojtaba Samareh Hashemi, one of Mr Ahmadinejad's most trusted advisers, a controversial and divisive figure with staunchly conservative views.
If so, the Iranian president will face a very tough task in securing mandatory approval from a recalcitrant parliament.
Mr Salehi's posting is also expected to be challenged by deputies who are likely to want a career foreign ministry diplomat in the sensitive position.
But, as a highly respected technocrat who is well regarded by Ayatollah Khamenei, Mr Salehi is likely to be more acceptable to parliament than some other figures Mr Ahmadinejad may put forward.
Mr Salehi is said to have been taken by surprise at his appointment, according to Farda News, a mouthpiece for Tehran's mayor, Mohammad Baqer Qalibaf, a conservative rival of Mr Ahmadinejad.
But he is likely to be well-prepared for his possible dismissal.
As the conservative daily Tehran-e Emrouz, another Qalibaf outlet, said in an editorial criticising the "unjustifiable" way Mr Mottaki was fired: "What is the guarantee that his successor won't meet the same fate?"