A major U.S.-led naval minesweeping exercise got underway in the Gulf Sunday as tension remain high over Iran and its controversial nuclear program.

The exercise kicked off on the same day the head of Iran's Revolutionary Guards warned of retaliation against the Strait of Hormuz, Israel and nearby U.S. bases if his country is attacked, and as Israeli Prime Minister Benjamin Netanyahu insisted on a "red line" from Washington, claiming Tehran is "90 percent" toward having a nuclear bomb.

Sudanese President Omar al-Bashir, who is wanted by the International Criminal Court, held talks with Egypt's Mohammed Morsi in Cairo on Sunday, officials said.

Bashir was met at Cairo's airport by Vice President Mahmud Mekki, and arrived with a large delegation of ministers.

The U.S. embassy in Yemen has suspended all consular services for two weeks, the mission said in a statement on its website, after four people were killed in violent anti-American protests in Sanaa.

The statement, published Saturday, said the embassy will be "closed for all consular services through September 29," warning citizens of the "potential" for protests near the mission.

International peace envoy to Syria Lakhdar Brahimi departed Damascus on Sunday after a four-day visit during which he met with President Bashar Assad, an AFP correspondent reported.

The veteran Algerian diplomat was seen leaving his hotel accompanied by Syria's deputy foreign minster Faisal Muqdad, and a U.N. official confirmed he was departing the country.

Libyan authorities have arrested at least 50 people in the wake of last week's killing of U.S. Ambassador Chris Stevens in a mob attack in the city of Benghazi, Libya's parliament chief said Sunday.

"The number reached about 50," Mohammed al-Megaryef, president of the Libyan National Congress, told CBS News in an interview.

The head of Iran's powerful Revolutionary Guards on Sunday warned of retaliation against the Gulf's strategic Strait of Hormuz, U.S. bases in the Middle East and Israel if his country was to be attacked.

General Mohammed Ali Jaafari, speaking in a very rare news conference in Tehran, also said that he believed Iran would abandon the nuclear Non-Proliferation Treaty should it be targeted for military action.

Militants attacked a security building in Egypt's Sinai on Sunday sparking clashes, while three policemen were wounded in separate fighting in the area, security officials told AFP.

The clashes erupted as armed men belonging to Islamic militant groups attacked the North Sinai security headquarters in the town of Al-Arish at dawn using rocket propelled grenades and automatic rifles, one official said.

Syrian troops on Sunday fought rebel fighters and shelled their bastions in the country's two main cities Damascus and Aleppo, a day after U.N. envoy Lakhdar Brahimi warned the conflict threatens world peace.

The fighting in Damascus erupted at dawn and was focused in the northeast suburb of Harasta, while the army shelled the southern suburb of Al-Hajar Al-Aswad from several directions, the Syrian Observatory for Human Rights said.

The United States on Saturday ordered non-essential diplomatic staff and their relatives to leave Sudan and Tunisia following violent anti-American protests, and warned U.S. citizens against travel to those countries.

Tunisia's Interior Ministry threatened to punish all those involved in Friday's U.S. embassy attack that left four people dead and 49 injured after extremist protesters angry over the amateur film made in the United States stormed the installation.

Gunmen shot dead four people including a police colonel in Iraq on Saturday, and a policeman was killed in a bombing, security and medical officials said.

Gunmen attacked a house in the village of Hajj Ali, south of the main northern city of Mosul, killing three cousins, police First Lieutenant Qahtan Nayef al-Juburi and Dr. Wissam Abboud from Mosul General Hospital said.