Israeli Prime Minister Benjamin Netanyahu said Sunday that a "military option" was "necessary" for the success of negotiations aimed at reining in Iran's disputed nuclear program.

Netanyahu said the Jewish state shared U.S. President Barack Obama's "preference" to pursue diplomacy "but for diplomacy to succeed, it must be coupled with powerful sanctions and a credible military threat."

Iran wants all foreign forces to leave Afghanistan, President Hassan Rouhani told his visiting Afghan counterpart Sunday amid a row between Kabul and Washington over a long-delayed security pact.

Iran "is opposed to the presence of any foreign force in the region, the Middle East, the Persian Gulf and particularly the Islamic country of Afghanistan,"Rouhani told Hamid Karzai, who was in Tehran for a one-day visit.

Scores of Saudi students were transferred from Lebanon to study in the U.S. and other countries after the deteriorating security situation in the country, the Saudi al-Yaum daily reported on Sunday.

The newspaper said that around 45 students, who were studying in Lebanese universities, have traveled to the U.S., the UK and Australia to continue their education there.

U.S. President Barack Obama warned Saturday that an "ideal" agreement to eliminate "every nut and bolt" of Iran's disputed nuclear program was not a realistic goal.

But he argued that the best possible available agreement with Tehran was likely to be better than the alternatives, and it was therefore imperative to try to secure one.

Afghan President Hamid Karzai is to visit Iran on Sunday straight after an awkward visit to Kabul by U.S. Defense Secretary Chuck Hagel, an Iranian official said.

To the growing dismay of Washington, Karzai has been refusing to sign a deal allowing NATO troops to stay in Afghanistan beyond next year, a position strongly backed by Iran.

Inspectors from the U.N. nuclear watchdog arrived in Iran Saturday to visit the still-unfinished Arak heavy water plant for the first time in more than two years, the ISNA news agency reported.

The two inspectors from the International Atomic Energy Agency will begin their work on Sunday at the site, 240 kilometers (150 miles) southwest of the capital, but ISNA did not say how long they would be there.

Iranian President Hassan Rouhani told university students Saturday that tolerance could resolve the issue of political prisoners, as some of them chanted for opposition leaders under house arrest to be freed.

"My government is committed to the promises it has made to the people, but we need to create internal consensus to achieve the objectives," Rouhani told students at Shahid Beheshti University in Tehran.

U.S. lawmakers are preparing a possible vote on new sanctions against Iran, a move President Barack Obama and his P5+1 partners fear could sabotage the nuclear deal reached in Geneva.

Administration officials have beaten a path to Capitol Hill in recent weeks, warning Congress against short-circuiting the delicate negotiations.

Diplomacy with Iran must be backed up by U.S. military might, Pentagon chief Chuck Hagel said Saturday in a speech addressed to Gulf allies anxious over a nuclear deal with Tehran.

Hagel promised the United States would maintain a 35,000-strong force in the Gulf region, as well as an armada of ships and warplanes, despite the recent deal with Tehran.

Russian Foreign Minister Sergei Lavrov is set to visit Tehran next week to discuss bilateral relations and Iran's nuclear program after its leadership agreed a landmark deal on limiting enrichment.

"A visit by Sergei Lavrov to Iran is planned for December 10 to 11," a spokeswoman for the foreign ministry told Agence France Presse.