Nairobi/Washington  - The African Union and the United States have imposed travel bans and sanctions on members of Guinea's junta as pressure grows on the regime to step down following a massacre of opposition supporters.

Security forces opened fire on an estimated 50,000 demonstrators at a stadium in the capital Conakry in late September, killing 157, according to a tally by a local human rights group.

The government claims only 57 died, crushed to death in a stampede.

"The United States imposed restrictions on travel to the United States by certain members of the military junta and the government, as well as other individuals who support policies or actions that undermine the restoration of democracy and the rule of law in Guinea," State Department spokesman Ian Kelly said in a statement Thursday.

The African Union said it had also imposed travel bans and would freeze the bank accounts of junta members.

The European Union and the Economic Community of West African States (ECOWAS) have already placed arms embargoes on the country.

Junta leader Captain Moussa Dadis Camara has tried to distance himself from the massacre - in which more than 1,200 were injured - blaming it on unruly soldiers.

However, New York-based Human Rights Watch this week said that the massacre was premeditated. Witnesses say troops shot, bayoneted and sexually assaulted protestors during the violence.

Camara was an unknown until he took control of the West African nation in December, following the death of strongman president Lansana Conte.

While Camara initially said he would not attempt to rule in the long-term, he is widely expected to announce he will run as a candidate in January 2010's presidential election.

It was this rumour that sparked the protests.

Analysts say that further opposition rallies and consequent violence are likely should Camara run. (dpa)