The United States is investigating whether Iran sent hundreds of special artillery shells for chemical weapons to the late Moammar Gadhafi regime in Libya, The Washington Post reported late Sunday.

The shells, which Libya had filled with mustard gas, were discovered in recent weeks at two sights in central Libya, the Post said citing unnamed U.S. and Libyan officials.

The "time has come" to deal with Iran, Israeli Defense Minister Ehud Barak said Sunday, refusing to rule out military action to curb the Islamic republic's nuclear ambitions.

Barak, speaking on CNN's Fareed Zakaria GPS program, indicated that Israel's patience was wearing thin -- and provided an ominous response when asked about the growing speculation of an Israeli military strike.

Italy's new foreign minister Giulio Terzi di Sant'Agata and his German counterpart Guido Westerwelle called for an end to violence in Syria and Egypt after talks on key European issues in Rome Sunday.

"The two ministers expressed deep concern for the escalation of violence in Syria" and reiterated their support for an Arab League roadmap for peace in the country, they said in a joint statement.

Saudi Crown Prince and Interior Minister Nayef bin Abdul Aziz discussed latest developments with French Foreign Minister Alain Juppe in Riyadh on Sunday, Saudi Arabia’s state news agency SPA reported.

The two officials discussed "the latest regional and international developments and subjects of mutual interest," SPA reported.

Moammar Gadhafi’s spymaster Abdullah Senussi was arrested on Sunday, Libyan officials announced and said that the dead dictator's son captured the previous day would face trial in Libya.

Ignoring world pressure, Libya's interim rulers insisted that Seif al-Islam, Gadhafi’s one-time heir apparent, would be tried inside Libya rather than at the International Criminal Court at The Hague.

At least four people were killed on Sunday as security forces tried to clear protesters from Cairo's Tahrir Square, casting a dark shadow over Egypt's first elections since Hosni Mubarak's downfall.

Police and military forces used batons, tear gas and birdshot to clear the central square of thousands of protesters who are demanding that the ruling military cede power to a civilian authority.

Syria's Foreign Minister Walid Muallem on Sunday dismissed as "wishful thinking" a warning by U.S. Secretary of State Hillary Clinton that his country risked descending into civil war.

"When Mrs. Clinton says the opposition is well-armed ... it is, as they say in English, 'wishful thinking'," Muallem told a news conference in Damascus.

Syrian anti-regime protesters and their Egyptian supporters clashed with backers of President Bashar al-Assad on Sunday outside the Arab League headquarters in Cairo.

The anti-Assad protesters, who had set up camp outside the Arab League, said about 150 Assad loyalists carrying a poster of the embattled president tried to attack their tent but they drove them off with the help of Egyptian protesters.

Turkish President Abdullah Gul said there was "no place for authoritarian regimes" in the Mediterranean region, heaping more pressure on the embattled Syrian regime, in comments published Sunday.

"I strongly believe that there is no place any more for authoritarian regimes -- single party systems that do not have accountability or transparency -- on the shores of the Mediterranean," he told Britain's Sunday Telegraph newspaper.

Arab foreign ministers are to hold crisis talks over Syria in Cairo on Thursday, the Arab League said after it rejected changes proposed by Damascus to its proposal to send an observer mission there.

"The Arab League council will hold an extraordinary meeting on Thursday, at the level of foreign ministers, and will be presided by Qatar," Arab League Deputy Secretary General Ahmed bin Hilli told reporters.