Iraq's Prime Minister Haider al-Abadi on Thursday welcomed Iran's assistance in the fight against Islamic State jihadists, but warned Tehran to respect Baghdad's sovereignty.

"Everything must be done through the government of Iraq," Abadi told an audience of U.S. policy experts at a Washington think tank on the third day of a visit to the United States.

Important talks between the U.N. atomic watchdog and Iran appeared Thursday to have failed to produce any breakthrough on a stalled probe into Tehran's alleged past efforts to develop nuclear weapons.

The International Atomic Energy Agency said in a short statement Thursday a day after a meeting in Tehran that the two sides would "continue this dialogue and agreed to meet again in the near future."

Al-Mustaqbal Movement slammed on Thursday Hizbullah, accusing it of prioritizing its subordination to the Islamic Republic of Iran over the Arab identity and Lebanese interests.

The statement that was published in al-Mustaqbal newspaper, the mouthpiece of the Sunni party, lashed out at Hizbullah, stressing that the party's allegations against al-Mustaqbal movement is merely a new attempt to impose the developments in Yemen on Lebanon.

Prime Minister Benjamin Netanyahu seized on Israel's annual remembrance of the Holocaust Wednesday to compare arch-foe Iran to Hitler's Germany.

"As the Nazis sought to stamp out civilization and to set the master race to rule across the earth... while wiping out the Jewish people, so does Iran seek to control the region, spread outwards and destroy the Jewish state," he said.

The U.N. atomic agency failed during talks in Tehran Wednesday to resolve long-standing questions over Iran's alleged past efforts to develop nuclear weapons, an Iranian official said.

"We discussed certain solutions to resolve the two outstanding questions, and it was decided to wind up the discussions at the next meeting," said Reza Najafi, Iran's ambassador to the International Atomic Energy Agency, quoted by ISNA news agency.

Iranian President Hassan Rouhani downplayed Wednesday the threat of U.S. congressional action against an eventual nuclear deal, saying Tehran is not negotiating with the lawmakers but with world powers.

The U.S. Senate foreign relations committee gave the green light Tuesday to a bill that would give Congress the right to review a possible final agreement on the Iranian nuclear issue.

Iran is to appoint a woman ambassador for the first time since its 1979 Islamic Revolution, according to unconfirmed media reports Wednesday.

The reports said foreign ministry spokeswoman Marzieh Afkham would be named ambassador to an Asian country.

Israel welcomed on Wednesday a compromise deal struck in Washington giving U.S. lawmakers a say on any final agreement on Iran's nuclear program.

Israel is bitterly opposed to the emerging agreement between Iran and world powers that would rein in but not halt Tehran's nuclear activities and has rallied its allies in the U.S. Congress in a bid to block it.

Possible skeletons in Iran's closet -- the subject of talks in Tehran on Wednesday -- could yet spook the historic Iran nuclear deal, experts say.

The U.N. nuclear watchdog conducts regular inspections of Iran's nuclear facilities and these will be increased if world powers and Iran can finalize their outline agreement by a June 30 deadline.

Iran's foreign minister said Wednesday that U.S. President Barack Obama was “responsible” for making sure that Washington respects a final agreement over Iran's nuclear program even though Congress has been given a say on the accord's fate.

"It is the obligation of the government of the United States to implement its international agreements. And we will hold the U.S. government, the U.S. president accountable" for the application of the treaties that they sign, Mohammad Javad Zarif told journalists in Lisbon.