Hundreds of former and would-be soldiers in Haiti refused government orders to disband and marched through the capital on Friday, a show of force that culminated in the evening with a tense exchange of gunfire with police outside an old military base.

The ex-soldiers and their young recruits have been pressing President Michel Martelly to honor his campaign goal of restoring the armed forces, which was abolished in 1995 because of its abusive record, holding marches in the capital, often in mismatching uniforms.

Friday's march began peacefully but some people near the National Palace threw rocks amid a heavy U.N. presence, whose troops responded by firing tear gas. A few of the men in military uniforms carried handguns.

U.N. spokeswoman Eliana Nabaa said earlier Friday that 40 to 50 of the marchers had been arrested by Haitian police because they were carrying illegal weapons and acting as if they were part of the disbanded military.

The gunfire between the police and former soldiers erupted late Friday. There were no immediate confirmed reports of casualties.

A police spokesman couldn't be reached immediately for comment late Friday.

Martelly has said he wants to revive the military but that it must be done legally. His administration has repeatedly called for the lightly armed men to drop their weapons and clear out of 10 bases they've taken over since February, including the one where the gunfire took place. But the government has taken little action to disband the group of men who've been parading about Haiti.