The United States said it "strongly supports" a West African arms embargo against Guinea, where dozens of opposition supporters have been killed in political violence.

The White House said it backed moves by members of the Ecowas bloc of West African nations to sanction Guinea following brutal violence that killed more than 100 people in September.

The United Nations estimates that about 150 people were killed in a Conakry stadium on 28 September when troops opened fire on a rally urging the junta leader not to stand in elections planned for January.

"The United States strongly supports the Economic Community of West African States' (Ecowas) decision to impose an arms embargo on Guinea and to work with the African Union to develop a regime of targeted sanctions against individuals," the White House statement said.

Hundreds have left the country

A UN probe has been established, with which Washington urged the parties to cooperate.

Hundreds of French nationals have left Guinea on the advice of the Paris government after the massacre of protestors against the military junta, an airport official said on Tuesday.

"Last week, flights to Paris were full," said Diawara Sirima of Conakry airport's immigration services.

"Several hundred people, mostly women and children, have already left the country," adjutant Sirima added.

"I'm leaving for a while," said the head of the French school in Conakry, Rodolphe Ratorete, as he went through the last security cordon at the capital's airport to take a flight for Paris.

Several hundred of the roughly 2500 French residents in the former colony in west Africa are leaving for France, but others have expressed the desire to stay and pointed out that Paris had given no orders.

The French foreign ministry last week "recommended that French nationals present (in Guinea) should leave," warning of a potential risk to their security in the aftermath of the violence.

Classes were immediately halted at the French school and almost all the teaching staff left. Ratorete said he hoped to be away "not for too long", and three secretaries have been handling outstanding business at the school pending its total closure.

Security situation has deteriorated

The ministry warned that "there is no prospect of an improvement in the short term". Its statement added that "the security situation has deteriorated in Conakry" and "bandit attacks have multiplied particularly armed attacks."

But Commissioner Bangaly Kourouma of the airport security service said: "There is no massive departure of the French from Guinea.

"We live in perfect understanding with our French friends in Guinea."

Kourouma added that the country was going through "a temporary crisis."

Several French nationals told AFP they were going to remain in Guinea, where the junta is under strong domestic and international pressure to back down and open the way for change.

"There was no evacuation order, we've decided to stay. My job is here," said Sophie, who had come to the airport with her partner to see off a friend.

Andre, the owner of a pastry shop, has lived in Guinea for more than 25 years, under the late Lansana Conte (1984-2008), then under the junta that seized power after his death. He was not prepared to leave his small business for an "adventure" in France.

'No xenophobic threat'

"They forced me to leave," stormed Sylvie, an aid worker who said that there was no "xenophobic threat" against the French community.

In a more measured tone, Sister Brigitte Busch from Fringabe monastery, at Kindia in the north, said "we were advised to leave (...) I intend to come back, rest assured, we're not disgusted by Guinea."

The United Nations estimates that about 150 people were killed on 28 September when troops opened fire on demonstrators who had gathered in a Conakry stadium to urge junta leader Captain Moussa Dadis Camara not to stand in elections the government had scheduled for January.

The junta says that 56 people were killed, while rights groups say that at least 157 people were massacred and more than 1200 were injured, including women who were brutally raped by soldiers.