By Martin Chulov and Ewen MacAskill

(The Guardian) — An armed insurrection inside Syria looks set to gather momentum after the failure to pass a UN resolution against president Bashar al-Assad’s regime, according to dissidents in two key Syrian cities.

Activists from Homs and Hama, where mostly peaceful protests over the past six months have lately become more aggressive and armed, say the failure of the US effort to threaten sanctions against Syria has convinced some that diplomacy cannot protect them.

“There’s no way out of this except to fight,” said an activist from Homs. “For the people of Homs the international community are not with us and we know that for sure. Russia and China will continue to protect Assad and as long as that happens, he will hunt us down.”

Britain, France and the US are expected to seek a fresh resolution on Syria before the UN Security Council after Russia and China on Tuesday night vetoed a draft that threatened sanctions, a security council source said.

The veto by Russia, supported by China, provoked the biggest verbal explosion from the US at the UN for years, with its ambassador Susan Rice expressing “outrage” over the Moscow and Beijing move.

Rice also walked out of the security council, the first such demonstration in recent years. While walk-outs are common at the UN general assembly, they are rare in the security council.

“It will not go away,” the source said. “It will not be next week. We don’t have a date. But there are a number of ways the security council can get back to this.”

The vote was 9-2 in favour, with four abstentions: South Africa, India, Brazil and Lebanon.

Rice, who before joining the Obama administration established a reputation as an outspoken critic of the failure of the west to intervene in humanitarian crises round the world, said after the vote: “The United States is outraged that this council has utterly failed to address an urgent moral challenge and a growing threat to regional peace and security.”

Without naming Russia and China but making it clear they were the target of her words, she said: “Let there be no doubt: this is not about military intervention. This is not about Libya. That is a cheap ruse by those who would rather sell arms to the Syrian regime than stand with the Syrian people.”

She added: “This is about whether this council, during a time of sweeping change in the Middle East, will stand with peaceful protestors crying out for freedom – or with a regime of thugs with guns that tramples human dignity and human rights.

“We deeply regret that some members of the council have prevented us from taking a principled stand against the Syrian regime’s brutal oppression of its people.”

The resolution had been weakened considerably since the original text was circulated to the 15 security council members in early August seeking to impose sanctions.

The draft resolution on Tuesday only said the security council would “consider its options” in 30 days’ time if Assad failed to stop the violence and seek a peaceful settlement of the crisis. It said the options would include sanctions. To further water down the resolution in an attempt to make it more acceptable to Russia and China, there was no hint of military intervention.

In Homs, where government forces are routinely clashing with armed members of the opposition – many of them former soldiers who defected with their weapons – outgunned protesters are now openly seeking weapons from outside the country.

“We know that we will not see Nato jets above the skies of Damascus,” said one Homs resident. “It is us against them. No one else will help us.”

In Beirut, where aid supplies to Homs and Hama are co-ordinated, aid workers said they had been receiving more requests for weapons than for food or medicine. “Of course we can’t help with this. But it shows how much their priorities have changed.”