French Foreign Minister Laurent Fabius has urged his Iranian counterpart Mohammad Javad Zarif to exert efforts to end Lebanon's presidential crisis, informed sources said.

The Iranian sources told pan-Arab daily al-Hayat published on Thursday that Fabius told Zarif about the importance of contacting Lebanese parties that are allied with Iran to urge them to find a solution to the deadlock.

U.S. Secretary of Defense Ashton Carter has sought to reassure worried lawmakers on the nuclear deal with Iran and stressed that the Islamic Republic and its proxies, including Hizbullah, continue to be a threat.

Iran and its proxies still present security challenges, Carter said on Wednesday at a committee hearing as part of the White House's aggressive campaign to convince Congress to back the Iranian nuclear deal, which calls on Iran to curb its nuclear program in exchange for billions of dollars in sanctions relief.

Top U.S. military officers sought to reassure worried lawmakers Wednesday that U.S. forces would check Iran's "malign" influence in the Middle East should Congress greenlight the nuclear deal with Tehran.

Many Republicans and some skeptical Democrats have voiced concerns that the historic accord reached with the Islamic republic this month in Vienna would trigger a regional nuclear arms race, embolden and strengthen Iran and put key U.S. ally Israel in jeopardy.

Iran's foreign minister moved to dismiss concerns Tuesday that his country's nuclear deal with major powers could hit difficulties, saying he had "no concern or worry" about its implementation.

Mohammad Javad Zarif's remarks came during a joint news conference with visiting EU foreign policy chief Federica Mogherini aimed at ensuring that the historic agreement swiftly takes effect.

Israeli Prime Minister Benjamin Netanyahu said Tuesday that Iran posed a "formidable" threat to Europe, accusing its proxy Hizbullah of operating cells across the continent.

Just last month, a member of the Lebanese group was jailed in Cyprus for plotting attacks on Israeli targets on the Mediterranean island.

A trip to Tehran by French Foreign Minister Laurent Fabius faced a threat of being overshadowed Tuesday by a tainted blood scandal from the 1980s which killed hundreds of Iranians.

Fabius is due in Tehran on Wednesday and Iran's conservative media carried attacks about the imported blood case which occurred when he was France's prime minister.

The lawyer of a Washington Post reporter jailed in Iran for espionage demanded Tuesday the release of her client, citing the new atmosphere after Tehran's nuclear agreement with world powers.

Her plea comes a week after Iranian-American reporter Jason Rezaian began his second year behind bars.

Saudi Arabia's foreign minister on Monday denounced "aggressive statements" by Iran, after Tehran accused Saudi ally Bahrain of stoking Gulf tensions by making unfounded allegations against it.

"This is unacceptable to us," Foreign Minister Adel al-Jubeir said at a joint news conference with visiting EU foreign policy chief Federica Mogherini.

EU foreign affairs chief Federica Mogherini held talks in Saudi Arabia Monday to explain the agreement she helped broker on Iran's nuclear program, and to push for an end to Yemen's war.

Mogherini met with Foreign Minister Adel al-Jubeir in the latest visit by a top Western official aimed at easing Saudi concerns over the deal with its regional rival.

Iran on Sunday accused Sunni-ruled Bahrain of stoking tensions in the Gulf by making unfounded allegations against it, the official IRNA news agency reported.

"It is clear that the government of Bahrain, by repeating unfounded allegations, seeks to create a climate of tension in the region," it quoted foreign ministry spokeswoman Marzieh Afkham as saying.