G8 leaders on Tuesday strongly endorsed calls for a peace conference to be held in Geneva on the Syria conflict "as soon as possible".

At the end of a summit in Northern Ireland, the leaders also called for an agreement on a Syrian transitional government "formed by mutual consent", and said the military and security services "must be preserved and restored" in a future set-up.

Quitting power while his government battles a countrywide uprising would be a "national betrayal," Syria's President Bashar Assad has told a German newspaper in an interview.

"If I decided to leave office under these circumstances, it would be national betrayal. But it's another question if that's what the people want," he told Frankfurter Allgemeine Zeitung.

Two suicide bombers blew themselves up at a Shiite Muslim religious hall in north Baghdad, killing at least 15 people, security officials said, the latest in a surge in nationwide violence.

The blasts took place shortly after midday prayers in the Habib ibn al-Mudhaher Hussainiyah in the capital's Qahira neighborhood, the interior ministry and police sources said.

Afghan government envoys are to travel to Qatar to try to open peace talks with the Taliban on a possible deal ending 12 years of conflict, President Hamid Karzai said Tuesday.

Karzai's announcement was a boost for the moribund peace process, which has made little ground despite mounting pressure as the withdrawal of 100,000 NATO troops from Afghanistan looms next year.

Senior leaders of the Palestinian Islamist movement Hamas will meet on Tuesday in Ankara with Turkish Prime Minister Recep Tayyip Erdogan, a diplomatic source told Agence France Presse.

The group's exiled leader Khaled Meshaal, along with Gaza's prime minister Ismail Haniya, will discuss Erdogan's planned visit to the Gaza Strip as well as the situation in Syria, the source said on condition of anonymity.

The planned peace conference in Geneva to end the conflict in Syria should not imply any capitulation on the part of the regime of Syrian President Bashar Assad, Russian Foreign Minister Sergei Lavrov was quoted as saying Tuesday.

"We are categorically against... assertions that the conference should be some kind of public act of capitulation by the government delegation followed by a handing over of power to the opposition," Lavrov told Kuwaiti news agency KUNA in an interview whose text was published by the Russian foreign ministry.

Syrian warplanes hit rebel positions near a contested military air base in the north on Tuesday, activists said, while President Bashar Assad's forces nearby pressed ahead with an offensive against opposition fighters in the country's largest city Aleppo.

The Britain-based Syrian Observatory for Human Rights said that fighter jets struck near the Kweiras air base near the Turkish border early Tuesday. Opposition forces fighting to oust Assad's regime for more than two years have been trying for months to take Kweiras and two other military air bases nearby.

Authorities in Kuwait on Tuesday hanged a 33-year-old Egyptian man dubbed a "monster" for the abduction and rape of 17 children under the age of 10, the public prosecution said.

Hajjaj Saadi, who was handed five death sentences, complained shortly before his execution that had not been given any assistance from the Egyptian government, a witness said.

Ethiopia and Egypt have agreed to hold further talks on the impact of an Ethiopian dam to quell tensions between the two countries, the foreign ministers of both nations said Tuesday.

"We agreed that we will start immediately on consultations at both the technical level... and the political level," Egyptian Foreign Minister Mohamed Kamel Amr told reporters, after meetings in Addis Ababa with his Ethiopian counterpart Tedros Adhanom.

As Shimon Peres turns 90, the indefatigable Israeli president is doing what he has always done: looking ahead, preparing for the next challenge and believing that he will see Middle East peace in his lifetime.

Old age has hardly slowed him down. If anything, it seems to have handed Peres a measure of the grace that eluded him as a younger man. And at a time when Israel is widely criticized for its ongoing occupation and continued settlement of war-won land, he operates as something of a one-man reminder that the country once aimed — in its 1948 Declaration of Independence — to be a "light unto the nations."