The United States opened a virtual online embassy Tuesday to reach out to Iranians despite the absence of official ties, vowing to break through the Islamic regime's "electronic curtain."

Iranian authorities have already voiced anger over the virtual embassy, accusing the United States of seeking to interfere in the country after Secretary of State Hillary Clinton announced plans for the project in October.

South Korea is reportedly pushing for U.S. permission to recycle spent nuclear fuel for power generation as the two countries resumed talks to revise a 1974 pact on the use of atomic energy.

The focus of the three-day talks until Thursday will be the peaceful use of nuclear energy, including Seoul's right to reprocess spent fuel, Yonhap news agency said.

A senior U.S. official on Monday urged South Korea and other allies to expand sanctions on imports from Iran for its suspected nuclear weapons program, calling the Islamic country "a pariah state".

Robert Einhorn, the U.S. State Department's special adviser for non-proliferation and arms control, said the allies should show a "clear and unified message".

A senior U.S. official said on Sunday that the world is looking for peaceful ways to end "killing and brutality" in Syria, accusing Iran of supporting the murder of Syrian people.

"While the goal of all us is to find ways to stop the killing and brutality, we are looking for peaceful ways to do so," Jeffrey Feltman, assistant secretary of state for near eastern affairs, told reporters in Amman.

Iran's military said it shot down a U.S. Army drone inside its territory near the Afghan and Pakistani borders on Sunday, and threatened to retaliate for the violation, Iranian media reported.

State-run Al-Alam Arabic language satellite channel, quoting a military source in Iran's joint chiefs of staff, said late Sunday the RQ-170 unmanned aerial vehicle was shot down "a few hours ago."

Herman Cain said Saturday he was suspending his campaign for the Republican nomination for the U.S. presidency, citing the pain caused to his family by repeated sexual misconduct allegations.

"I am suspending my presidential campaign because of the continued distraction, the continued hurt caused on me and my family," he told supporters in a typically stoic and emotionally charged speech in Atlanta, Georgia.

U.S. Assistant Secretary of State for Near Eastern Affairs Jeffrey Feltman is expected to visit Lebanon next week where he will hold talks with a number of Lebanese officials on the latest regional developments.

Al-Joumhouriya newspaper reported on Saturday that he will stress the need for Lebanon to respect the international sanctions against Syria, warning against any Syrian attempts to avoid these sanctions.

U.S. Secretary of State Hillary Rodham Clinton and Myanmar opposition leader Aung San Suu Kyi, two of the world's most recognizable women leaders, pledged on Friday to work together to bring democracy to Suu Kyi's long isolated and repressive nation.

Wrapping up a historic three-day visit to Myanmar, Clinton held hands with Suu Kyi on the porch of the Nobel peace laureate's lakeside home where she spent much of the past two decades under house arrest and thanked her for a her "steadfast and very clear leadership." The meeting was the second in as many days for the pair who appeared to have bonded almost as sisters after a private, one-on-one dinner in Yangon on Thursday.

U.S. Deputy Assistant Secretary of State for Population, Refugee, and Migration Affairs Kelly Clements has underscored the important responsibility of Lebanon to ensure the safety of Syrian refugees, the U.S. embassy said in a statement.

Clements held talks with Social Affairs Minister Wael Abou Faour, Higher Relief Council Secretary General Ibrahim Bashir, and senior officials from the U.N. High Commission for Refugees (UNHCR) and the U.N. Relief and Works Agency for Palestine Refugees in the Near East (UNRWA) on Thursday, the statement said.

Washington on Thursday placed economic sanctions on a senior Syrian general and a financier uncle of President Bashar al-Assad, adding new pressure on the regime over its bloody political crackdown.

The Treasury Department added Mohammed Makhlouf, Assad's maternal uncle and the father of already-sanctioned telecoms magnate Rami Makhlouf, and 4th armored division General Aus Aslan, to its growing list of Syrian figures and organizations that Americans are banned from doing business with.