Huge rival protests split the Yemeni capital as security forces staged an unprecedented deployment in another Friday showdown on the streets between supporters and opponents of President Ali Abdullah Saleh.

Amid fears of an outbreak of violence, tens of thousands of pro-regime supporters waving flags and banners gathered in squares around Sanaa, passing through checkpoints set up by security forces kitted with guns and batons.

Germany's foreign minister said Friday the situation in Libya could not be solved through "military means" and called for a ceasefire, amid a NATO-led air campaign against Moammar Gadhafi's forces.

Guido Westerwelle made the comments after meeting his Chinese counterpart Yang Jiechi in Beijing on an official trip that will be followed by a visit to disaster-struck Japan.

Israel's government watchdog announced on Thursday he would investigate Prime Minister Benjamin Netanyahu amid accusations private businessmen paid for lavish trips for him and his family.

State Comptroller Micha Lindenstrauss said he would probe whether the funding for the trips did not "contravene accepted norms of conflict of interest for ministers."

The United States urged Americans on Thursday to avoid travel to Syria and advised those already there to consider leaving a country that is reeling from weeks of deadly political unrest.

"We urge U.S. citizens to defer non-essential travel to Syria at this time. U.S. citizens currently in Syria should consider departing," the State Department said in a statement.

Iranian Foreign Minister Ali Akbar Salehi on Thursday dismissed as a "conspiracy" against Muslim countries the death sentence announced by Kuwait against spies allegedly linked to Iran, the official IRNA news agency reported.

Salehi made the remarks in a telephone conversation with his Kuwaiti counterpart Mohammed al-Sabah, who had earlier announced that an unspecified number of Iranian diplomats would be expelled for alleged spying since the 2003 invasion of Iraq.

Libyan leader Moammar Gadhafi warned on Thursday that the West has started something in Libya which it cannot control, the state news agency JANA reported.

"They have started something dangerous, something they cannot control. It will be out of their control no matter what methods of destruction they have at their disposal," Gadhafi said.

Syria is launching an immediate probe into the deaths of "civilians and troops" in Daraa and Latakia, two cities that have emerged as the focal points of protests, state media reported Thursday.

"Syrian President Bashar al-Assad has charged the head of the judges' council with forming a committee to begin an investigation, effective immediately, into the deaths of civilians and troops in the governorates of Daraa and Latakia," read a report on the state-run news agency SANA.

The West intervened in Libya after the Arab League, many of whose members also face revolts, failed to live up to its duty to protect civilians, Qatar's emir said in an interview broadcast on Thursday.

Sheikh Hamad bin Khalifa al-Thani told Al-Jazeera television, based in Doha, he hoped the 22-member organization would now step up and meet its responsibility "amidst the ongoing changes" sweeping the region.

A Reuters journalist of Jordanian nationality has gone missing in unrest-hit Syria, the Amman government announced Thursday, saying it was seeking information about his whereabouts.

"The Jordanian consul in Damascus is trying to get information from the Syrian authorities about Suleiman Khalidi of the Reuters bureau in Amman. He went to Damascus but no one heard from him since Tuesday," foreign ministry spokesman Mohammed Kayed told Agence France Presse.

The Syrian Observatory for Human Rights said it received a letter from Syrian political detainees in Damascus Central Prison calling for peaceful demonstrations on Friday for the sake of “freedom, justice and equality.”

“The hour of truth has arrived and comprehensive change is the only choice left,” it added.