Those responsible for attacks on U.N. observers in Syria must be brought to justice, U.N. rights chief Navi Pillay said Monday.

"We must make our utmost possible efforts to ensure accountability for all perpetrators, including those who have attacked U.N. observers in Syria," Pillay told a meeting of the Human Rights Council.

Two Palestinians were killed in an Israeli strike on north Gaza on Monday, medics said, just hours after gunmen mounted a deadly ambush on the Egyptian border, killing an Israeli.

"Two Palestinians were killed in an Israeli air strike targeting a group of people east of Beit Hanun," said Adham Abu Selmiya, spokesman for the Hamas-run emergency services.

Russia is preparing to send two amphibious assault ships to the Syrian port of Tartus where Moscow operates a strategic naval base to ensure safety of its nationals, the Interfax news agency reported Monday.

"Two major amphibious ships -- The Nikolai Filchenkov and The Tsezar Kunikov -- are preparing to be dispatched to Tartus outside of their schedule," the Russian news agency quoted an unidentified officer from the Russian naval headquarters as saying.

Syrian forces pounded Homs on Monday as they pressed their campaign against rebel strongholds in the city, while 34 people were killed across the strife-torn country, a watchdog said.

Monday's casualties come a day after 67 people were killed nationwide, including 15 in Homs province, the Syrian Observatory for Human Rights said.

A suicide bomber killed on Monday Yemen's southern army commander, General Salem Ali Qoton, in an attack in the port city of Aden, a medical official told Agence France Presse.

"General Qoton was killed and four others were wounded in a suicide attack," near his home in the Mansoura neighborhood of Aden, the medic said.

Israel was still hunting for up to four gunmen who on Monday infiltrated the Egyptian border and staged a deadly ambush, killing one Israeli and sparking a firefight which left two militants dead.

The incident began around 6:00 am (0300 GMT) when a group of up to six gunmen opened fire towards a convoy of vehicles carrying Israeli construction workers to a site where they are building part of the vast border fence, the army said.

The campaign of Egyptian presidential candidate Ahmed Shafiq said on Monday it rejected a claim by the Muslim Brotherhood that its candidate Mohammed Mursi had won a historic presidential election.

"We reject it completely," Shafiq campaign official Mahmoud Barakeh told reporters of the Brotherhood's proclaimed victory.

The opposition Syrian National Council issued a cry for help Sunday to save Homs and other cities from attacks by President Bashar Assad's regime, and repeated its call for U.N. intervention.

"The country is under a violent attack, especially Homs," said Abdel Basset Sayda, the leader of the SNC, Syria's main opposition group.

Activists gathered at Cairo's iconic Tahrir Square warned Egypt's ruling military on Sunday they stand ready to reignite the revolution if the army clings to power.

"We're still here to carry the torch" of the revolution, warned Marwan Adel at the square which in February 2011 became the cradle of the uprising that ousted former president Hosni Mubarak.

Egypt's ruling military council is to stay in control of legislation and the budget in the absence of a parliament, even as the country prepares to announce a new president, military sources told Agence France Presse Sunday.

The Supreme Council of the Armed Forces (SCAF), which took power when president Hosni Mubarak was ousted in an uprising last year, is set to issue an amended constitutional declaration, consolidating its powers just hours before Egypt wraps up a divisive presidential election to pick Mubarak's successor.