PORT-AU-PRINCE, Haiti (AP) _ Haiti's military-backed president declared a state of emergency Sunday, urging Haitians to unite to withstand a world embargo and oppose possible foreign military intervention.

''I ask you tonight to mobilize for the defense of the country,'' 81-year- old Emile Jonassaint said in an address broadcast shortly after 2 a.m. on state television. ''Haiti will not give in to the injunctions of the foreigner.''

The speech followed President Clinton's tightening of sanctions Friday on Haiti's military coup leaders. Clinton announced an end to most financial transactions between the United States and Haiti and banned all U.S. commercial flights to the Caribbean nation after June 25.

''The state of emergency is declared throughout the country,'' Jonassaint said, first in French and then in Creole, Haiti's two official languages.

Jonassaint did not specifically mention the new U.S. action nor detail what measures would be undertaken under the state of emergency, promising only ''a series of measures.''

He urged Haitians to fight to the death ''to resist any foreign intervention.''

He recalled similar resistance from the nation's founding fathers, who ousted French slaveholder colonists in 1804, making Haiti the world's first black republic.

Jonassaint was installed by the army on May 11 in a ceremony denounced by the United States and other nations as illegal. They continue to recognize constitutionally elected President Jean-Bertrand Aristide, who was ousted by the military in September 1991.

Jonassaint said he was ''ashamed'' that he voted for Aristide and said that the elected leader did not represent democracy.

Aristide, a widely popular leftist priest, won Haiti's first free elections in December 1990 with a landslide.

Jonassaint's appointment formalized the military's break in negotiations with the United Nations on a peaceful end to the crisis. Before the sanctions announced by Clinton on Friday, Haiti already had been reeling under a U.N. oil embargo imposed last fall and an near-complete ban on trade with Haiti imposed several weeks ago.

The Clinton administration has said that it has not ruled out military intervention to restore the elected government.

''There's a giant crushing us because we are weak and we don't have the atom bomb,'' Jonassaint said. ''If we had the atom bomb then everyone would respect us.''

He said the international community thinks it can do ''anything in Haiti.''

Jonassaint said he feels sorry for Haitians who have recommended military intervention. That was a possible reference to Aristide's premier, Robert Malval, who has publicly urged Haitians to disobey the rule of Jonassaint and army commander Lt. Gen. Raoul Cedras.

Malval said last week that Haitians would more likely support the U.S. military than their own in the event of an intervention.

Jonassaint's message was broadcast after state TV finished showing ''The Longest Day,'' the movie about the D-Day invasion, and a reading of Haiti's act of independence.

The army-backed government has been cautious to prevent a blatant provocation of foreign powers. However, radio reports have indicated the government was considering closing the international airport several days before U.S. and Canadian jetliners halt commerical flights to Haiti on June 25.

Both American and Canadian embassies have urged their nationals to leave before then.