Egyptian military helicopters on Friday carried out air strikes on Islamist militant positions in Sinai, two days after suicide bombers killed six soldiers in the restive peninsula, security sources said.

Apache helicopters targeted hideouts and vehicles used by the militants near the town of Sheikh Zuwayid in northern Sinai, the sources said.

Syria's opposition National Coalition said Friday it was "deeply skeptical" about the government's decision to join a chemical weapons ban and urged a tough U.N. resolution to enforce the measure.

Its statement came a day after Damascus filed documents at the United Nations seeking to join the international convention banning chemical weapons.

State news agency SANA said on Friday it and other government websites in conflict-plagued Syria have come under attack by hackers, complicating access to their sites.

It did not specify the origin of the attacks.

U.S. Secretary of State John Kerry said Friday he would meet again with his Russian counterpart Sergei Lavrov in New York later this month to try to set a date for a long-delayed peace conference for Syria.

"We both agreed... to meet again in New York around the time of the U.N. General Assembly around the 28th in order to see if it is possible then to find a date for that conference," Kerry told reporters at a joint press briefing in Geneva with Lavrov and the U.N.-Arab League envoy to Syria, Lakhdar Brahimi.

Israel on Friday closed off the Palestinian territories for 48 hours, ahead of the solemn Jewish holiday of Yom Kippur which begins at sunset.

A military spokesman told Agence France Presse that crossings were closed from midnight Thursday and would reopen at midnight on Saturday.

President Vladimir Putin on Friday won the support of Iran and China at a regional summit on Russia's initiative for Syria to hand over its chemical weapons, which he said had proved the "serious intentions" of the Damascus regime.

Putin attended the summit of the Shanghai Cooperation Organization (SCO), a regional security group sometimes seen as an eastern counterweight to NATO, in Kyrgyzstan a day after President Bashar Assad said he supported the Russian plan.

Syrian regime forces executed at least 248 people in the villages of Bayda and Banias earlier this year, Human Rights Watch said Friday, calling for Damascus to be held accountable.

In a report, the New York-based rights group said it had compiled a list of the names of 248 people killed in the two villages in coastal Tartus province on May 2 and 3.

Syria has scattered its stockpile of chemical weapons to as many as 50 sites in a bid to complicate U.S. efforts to track them, the Wall Street Journal reported Thursday.

A secretive Syrian military unit had been given responsibility to shift the arsenal of poison gases and munitions, raising questions about the viability of a Russian plan to secure the weapons, the report said, citing U.S. and Middle Eastern officials.

Syria on Thursday sought membership of the global convention banning chemical weapons, in a move that could help head off a western military strike.

Damascus said it now considers itself a full member of the convention. While U.N. leader Ban Ki-moon welcomed the application, the United Nations would not immediately confirm it had been accepted.

The United States called again Thursday on Egypt's interim authorities to lift a state of emergency in force since August, which Cairo said it is extending for two months.

"We remain opposed, as we have from the beginning, to the state of emergency. And we urge the interim government to end it immediately," State Department deputy spokeswoman Marie Harf told reporters.