Syrian helicopter gunships fired machineguns to disperse a large pro-democracy protest in the town of Maarat al-Numaan on Friday, witnesses said, in the first reported use of air power to quell protests in Syria's uprising.

The Syrian Observatory for Human Rights confirmed that helicopters fired at the town after security forces on the ground killed five protesters, but said no killings were reported in the assault by the helicopters.

Open gallery view Syrians living in Greece burn posters of Syrian President Bashar Assad, in solidarity with anti-government protesters in Syria, outside the Syrian embassy in Athens, May 6, 2011. Credit: Reuters

Two witnesses said they saw at least five helicopters.

Assad isn't taking Ban Ki-moon's phone calls

Also on Friday, Syrian President Bashar al-Assad, who is facing international pressure to end the bloody crackdown on anti-government protesters, is not taking the UN chief's phone calls, the United Nations said.

UN spokesman Martin Nesirky confirmed a report by Kuwait news agency KUNA that Secretary-General Ban Ki-moon had been trying to call Assad on Thursday but was told that the president was "not available."

He added that Ban had been trying to speak with Assad all week but was unable to get through to him.

Ban has urged Assad to end what he called "violent repression" and human rights abuses by Syrian forces, who rights groups say have killed over 1,100 civilians since March in their revolt to press demands for more political freedoms and an end to corruption and poverty.

A Syrian activist group said Syrian security forces killed 28 civilians at pro-democracy demonstrations on Friday. The figure could not be independently confirmed.

UN humanitarian chief Valerie Amos has asked Syria to allow a humanitarian team into the country to assess the situation. After initially agreeing to consider the request, Assad has made no move to grant it, UN officials say.

Separately, UN Security Council diplomats met again in New York on Friday in an attempt to break their deadlock on a European-drafted resolution that would not impose sanctions on

Syria but would condemn it for the crackdown and suggest Syrian security forces might be guilty of crimes against humanity.

Veto threat

Diplomats said Friday's meeting produced no changes among the 15 Security Council members. Currently nine council members, including the draft's sponsors Britain, France,

Germany and Portugal, plan to vote for it.

They said the draft could be put to a vote next week.

Russia and China dislike the idea of any council discussion of the issue and have suggested they might use their veto power to kill the resolution. Lebanon, which has a complicated

relationship to neighbor Syria, also opposes it.

India, Brazil and South Africa have also made clear they have problems with the draft, UN diplomats say.

The United States is not sponsoring the resolution but has made clear it supports the text. Washington, however, is not convinced that a Security Council resolution, which might be vetoed by the Russians and which Assad will almost certainly ignore, has much value, UN diplomats told Reuters.

Envoys said Britain and France are growing frustrated with South Africa, Brazil and India -- politically powerful developing nations with ambitions of eventually becoming permanent members of an expanded Security Council -- for resisting the idea of condemning Damascus.

A decision on Thursday by the UN nuclear watchdog in Vienna to report Syria to the Security Council for possible punitive action due to covert Syrian atomic work will be dealt with separately from the crackdown on protesters, envoys said.

They say that Russia will likely try to block any Western attempt to have the Security Council sanction Syria over its nuclear program.

