U.S. Secretary of State John Kerry walks with
U.S. Secretary of State John Kerry walks withAFP photo

Syrian opposition leaders renewed their appeals for arms at a meeting with U.S. Secretary of State John Kerry on Wednesday, but a top jihadist group's pledge of loyalty to Al-Qaeda deepened Western concerns that weapons could fall into the wrong hands.

AFP reported that Kerry and other G8 foreign ministers held talks with members of the Syrian National Coalition, including opposition prime minister Ghassan Hitto, on the sidelines of a two-day ministerial meeting in London.

The U.S. said it was mulling ways to step up help for Syria's rebels, while Kerry also met with Russian Foreign Minister Sergei Lavrov in a bid to find common ground on ending the conflict between the rebels and President Bashar Al-Assad.

Kerry will meanwhile attend a "Friends of Syria" core group meeting on April 20 in Istanbul, a U.S. official said, according to AFP.

However, a statement on Wednesday by the head of Syria's jihadist Al-Nusra Front pledging allegiance to Al-Qaeda chief Ayman al-Zawahiri will only increase Western doubts about arming the rebels.

The statement came several days after leader of the Al-Qaeda terrorist group, Ayman al-Zawahiri, urged rebels to fight to establish an Islamic state in Syria.

Islamist rebel groups such as the Al-Nusra Front, which has links to Al-Qaeda, have eschewed the main opposition National Coalition.

Al-Nusra is one of 13 factions in the radical Islamist rebel council that announced its secession from the main opposition force and declared its own Islamic state in Aleppo.

A top State Department official confirmed that, during a lunch hosted by British Foreign Secretary William Hague, the Syrian opposition leaders renewed appeals for lethal aid but Kerry "didn't promise anything."

The U.S. and EU are currently providing non-lethal aid such as communications equipment, and are beginning to distribute food and medical supplies to the Free Syrian Army, but have stopped short of providing weaponry.

The announcement by the Al-Nusra front is likely to bolster assertions by Assad's regime that it is fighting "terrorists" who want to impose an Islamic state, noted AFP.

"We are always considering a variety of options, we are going to continue to aid the opposition, working with them in terms of what they need, in terms of what we're willing to provide," the U.S. official said.

Wednesday's talks had focused on ways of changing Assad's calculations about the outcome of the conflict which is now in its third year and has cost some 70,000 lives, according to the UN.

"We need to have this continuing conversation which is why we are going back to Istanbul," the official said, according to AFP.

But he said the lunch with six Syrian opposition leaders was "a good, substantive discussion."

All sides emphasized "the importance of working together, the importance of them getting themselves more organized, which they said they were in the process of doing," he added.

The Syria conflict was also "top of the agenda" as the G8 foreign ministers met for dinner late Wednesday, Hague confirmed.