The United States is studying whether war crimes charges can be brought against Syria to pressure its regime to end a bloody crackdown on dissent, a senior administration official said Friday.

The official said other measures, including sanctions targeting the country's oil and gas sector, were being considered as part of a broader diplomatic campaign to increase pressure on Syria's President Bashar Assad.

Thousands of Shiite Bahrainis rallied Friday outside Manama in the second mass demonstration organized by al-Wefaq opposition group since a mid-March crackdown on pro-democracy protests.

Demonstrators gathered on the island of Sitra south of Manama for the rally, a week after another protest was held in another Shiite village with the blessings of the authorities, according to al-Wefaq's Facebook page.

Hours after loud blasts shook Libya's capital Tripoli, Moammar Gadhafi vowed to defeat NATO as his forces launched a deadly rocket assault on rebel-held Misrata.

State television on Friday aired Gadhafi's comments in what it said was a live telephone call from the Libyan leader, who has gone underground since Western nations began waging an air war in March to protect civilians from a bloody protest crackdown.

Syrian security forces killed at least 12 people when they opened fire on protesters on Friday, rights activists said, as France urged tougher EU sanctions against President Bashar al-Assad's regime.

The protests after the main weekly Muslim prayers came as the army pressed its campaign against northern towns and the number of refugees fleeing across the border into Turkey neared 10,000.

Libyan rebel chief Mahmoud Jibril denied Friday suggestions by a Russian envoy that the insurgents had been negotiating with Moammer Gadhafi's regime.

"I can assure you there is and there was no negotiation between the NTC and the regime," the head of the rebel National Transitional Council told a press conference in Naples.

Syria's ambassador to France has lodged an official complaint against the news channel France 24 accusing it of misinformation, the state-run SANA news agency reported Friday.

Lamia Shakkur filed the complaint to the Paris public prosecutor on Wednesday "for broadcasting false information," the Syrian embassy in France said in a statement carried by SANA.

Embattled Yemeni President Ali Abdullah Saleh, being treated for shrapnel wounds in Riyadh, will not return home, a top Saudi official told Agence France Presse on Friday, contrary to Sanaa's claims that he will return soon.

"The Yemeni president will not return to Yemen," the official said, requesting anonymity.

Two loud blasts shook Libya's capital Tripoli on Friday afternoon following a series of more distant explosions heard earlier in the day, an Agence France Presse journalist said.

Tripoli has been targeted anew by NATO warplanes, which since Thursday have been constantly overflying the Libyan capital.

Israeli Foreign Minister Avigdor Lieberman on Friday bluntly told the European Union's top diplomat that U.N. recognition of a Palestinian state in September would render the Oslo Accords null and void.

At a breakfast meeting with EU foreign policy chief Catherine Ashton, Lieberman said the 1993 Oslo Accords that created the Palestinian Authority, and all the agreements reached since then, would be cancelled if they secured recognition of their independent state when the United Nations meets this autumn.

U.N. chief Ban Ki-moon on Thursday urged Syrian President Bashar Assad's regime "to stop killing people," as pressure mounted on Damascus over its widening crackdown in the north.

Ban, who was in Brazil as part of a Latin America tour in support of his bid for re-election as secretary-general, told reporters Assad should "engage in an inclusive dialogue" and "take bold... measures before it is too late."