A Bahraini military court sentenced four Shiite protesters to death and three others to life in prison Thursday over the of killing two policemen when security forces crushed a pro-democracy protest last month, a Shiite opposition official said.

Ali Abdullah Hasan, Qassem Hasan Mattar, Saeed Abdul Jalil Saeed and Abdul Aziz Abdullah Ibrahim were sentenced to death, ex-MP from Al-Wefaq Shiite opposition group, Matar Matar, told Agence France Presse.

Britain on Thursday withdrew the Syrian ambassador's invitation to the wedding of Prince William and Kate Middleton, saying the regime's crackdown on protesters made his presence "unacceptable".

Foreign Secretary William Hague made the decision and the royal family agreed that Sami Khiyami should not attend Friday's ceremony, the Foreign Office said in a statement, following criticism from rights groups.

Gunmen using silenced pistols shot dead a senior Iraqi general in Baghdad on Thursday, an official said, the latest in a spate of assassinations of top military and civilian officials.

The killing of Brigadier General Mohammed Alaa Jassim was the fourth of a senior Iraqi official in the past week, with at least three others having narrowly escaped death in that time.

A Facebook group has called for protests on Friday against President Bashar al-Assad's regime and in solidarity with the southern town of Daraa, where troops and tanks have taken over the streets, Agence France Presse reported on Thursday.

"Friday of Anger, April 29, in solidarity with Daraa," says a notice on the Syrian Revolution 2011 page of Facebook, a motor of the protests in which demonstrators inspired by uprisings elsewhere in the Arab world are seeking greater freedoms.

The Palestinian unity deal agreed in Cairo crossed "a red line," Israel's Avigdor Lieberman said on Thursday, warning that an array of measures could be taken against the Palestinian Authority.

"With this accord, a red line has been crossed," the ultra-nationalist foreign minister told Israel's military radio a day after the Palestinian parties announced a surprise reconciliation agreement.

The 15-nation U.N. Security Council failed on Wednesday to agree a statement to condemn the killing of Syrian protesters, diplomats said.

After talks ended in deadlock, western nations called for an immediate open meeting of the Security Council so that international anger over the crackdown by the Syrian government could be highlighted.

Influential U.S. Senator John McCain declared Wednesday that Syrian President Bashar al-Assad has "lost his legitimacy" and called for U.N. sanctions to force him to halt attacks on his people.

But McCain told Agence France Presse he could not see any opening for U.S. military action to topple the Syrian regime, and regretted that Assad was not yet facing an armed revolt like the one fighting to oust Libya's Moammar Gadhafi.

Another 203 members of Syria's ruling Baath party announced their resignation Wednesday in protest at the deadly crackdown on protesters, raising the number to 233, according to lists seen by Agence France Presse.

The latest group to step down were members from the Houran region, which covers the flashpoint town of Daraa in the south of the country. Earlier 30 members resigned from the restive city of Banias in northwest Syria.

Rival Palestinian groups Hamas and Fatah reached an "understanding" in Cairo on Wednesday to set up a transitional unity government and to hold elections, prompting a swift warning from Israel.

Israeli Prime Minister Benjamin Netanyahu demanded that Palestinian president Mahmoud Abbas, who heads Fatah, "choose between peace with Israel or peace with Hamas."

Two Yemeni policemen and a protester were killed in clashes Wednesday in the country's main southern city of Aden, a security official and medics told Agence France Presse.

"Two Yemeni policemen were killed in a clash between security forces and protesters," the security official said.