Britain is to recognise the Syrian opposition as a "legitimate representative" of the country's people, William Hague has pledged.

The Foreign Secretary made the comment as he arrived in Tunisia for talks on how to respond to brutal repression by Bashar al Assad's regime.

He said the international community had to tighten the diplomatic and economic stranglehold on the Syrian Government, amid growing concern over bloodshed in Homs and other cities.

At the same time Russia, which vetoed sanctions against Syria at the UN Security Council, has called for an urgent ceasefire in Homs, while still maintaining that both the opposition and President Assad's regime were responsible for the bloodshsed.

Mr Hague said: "We will intensify our links with the opposition. I will meet leaders of the Syrian National Council (SNC) in a few minutes' time, before the main meeting takes place. We, in common with other nations, will now treat them and recognise them as a legitimate representative of the Syrian people."

He denounced Mr Assad's Government as "a criminal regime", but indicated Britain is not contemplating sending arms to the opposition. Mr Hague said: "There may well be people who say that [arms should be sent] and it reflects the intense frustration we all feel."

Mr Hague said he hoped the Chinese Government, which also refused to back sanctions, would change its position. "I haven't seen that shift in Russia yet," said the Foreign Secretary. "I think the Chinese Government is constantly assessing the position and so I hope... immediately they will change their position, but if not that, then they will steadily do so over time."

The SNC appealed to "Friends of Syria" to arm the rebel Free Syrian Army and support the popular resistance.

"If the regime fails to accept the terms of the political initiative outlined by the Arab League and end violence against citizens, the Friends of Syria should not constrain individual countries from aiding the Syrian opposition by means of military advisers, training and provision of arms to defend themselves," the SNC said in a statement to the international meeting in Tunis.

Arab and Western powers are divided over whether to arm Syria's rebels, with officials concerned such measures will worsen violence and suck in neighbouring countries backing different sides.

While the Free Syrian Army, made up mainly of army defectors, has been able to smuggle in weapons and buy them on the black market, Syrian opposition figures said there was no formal foreign military support for the opposition so far.

In Homs, Syrian Government artillery fire killed five people early yesterday.

Meanwhile, the International Committee of the Red Cross has not had any reply from Syrian authorities on its request for a truce to allow in aid supplies and evacuate the wounded.

The Russian Foreign Ministry urged both sides in Homs to cooperate with the Red Cross mission and with UN humanitarian envoy Valerie Amos.

"The priority should be the provision of a mutual, swift ceasefire for the removal of the wounded and injured from Homs, and urgent measures to satisfy the pressing humanitarian needs of residents in battle zones," its statement said.