LIMA, Peru (AP)—Amid heavy security to guard against terrorists, Peruvians on Sunday approved a constitutional referendum seen as a vote of confidence in President Alberto Fujimori, according to exit polls.

‘‘Now we have the tools for progress, I have no doubt that Peru is going to become the center of development in Latin America,’‘ Fujimori said at a victory news conference.

Preliminary exit polls by the country’s most respected polling firm, Apoyo, showed 55.3 percent in favor of the constitution and 44.7 percent against.

Apoyo did not give a margin of error, but its projections in past elections have been extremely accurate. Official results are expected within five days.

Fujimori suspended the old constitution, dissolved the legislature and seized special powers in April 1992, saying the moves were necessary to get control of the economy and put down a Maoist insurgency.

Approval of the new constitution would endorse his mandate and restore legitimacy to his government. It also would allow him to run for re-election in 1995.

‘‘This constitution will give Fujimori the power to do whatever he wants,’‘ said Fernando Rospigliosi, a political scientist at the Center for Peruvian Studies. The presence of observers from the Organization of American States will help Fujimori’s international standing, he added.

The vote was closer than expected. The government had been counting on a 60 percent approval rating.

Analysts said the lower than expected support reflected disapproval over Fujimori’s handling of the economy, which is in a deep recession. His free-market reforms and austerity measures have thrown thousands out of work and made millions poorer.

A last-minute bombing campaign by the Shining Path guerrillas also apparently cut into Fujimori’s support.

But Fujimori stressed the win above all else. ‘‘It’s been a hard three years, and this triumph is really satisfying,’‘ he said.

Voter turnout was heavy, and officials decided to let the polls stay open an extra hour.

Since grabbing his special powers, Fujimori scored a major victory in the eyes of his constituents with the capture of Abimael Guzman, leader of the Shining Path guerrillas who have terrorized the country for 13 years.

Army and police troop carriers patrolled Lima’s main streets and helicopters crisscrossed the skies Sunday to prevent attacks by the Shining Path. Early Sunday, the rebels dynamited a bank in the working-class district of Independencia, shattering windows and buckling doors, but causing no casualties, police said.

A series of rebel bombings has left at least six dead and 60 wounded in the past 10 days, apparently to express rejection of peace talks proposed by Guzman, who is serving a life sentence in prison.

Fujimori has said he will not negotiate with Guzman unless he orders his followers to lay down their arms. Nearly 30,000 people have died in the insurgency.

Sunday’s balloting was the first direct, nationwide ballot on a constitution. In its 172-year history as a republic, Peru has had 11 charters approved by the president or by constituent assemblies.

Fujimori’s backers say the new constitution encourages private investment and limits the role of the state in basic services such as education and health care, in keeping with the free market reforms sweeping Latin America and other parts of the world.

Critics say the constitution cuts workers’ rights, limits free education and gives Fujimori too much power.

Allowing the president to run for consecutive terms is rare in Latin America. Fujimori’s supporters say his re-election is necessary to maintain stability in political and economic programs. Opponents say history has demonstrated in Peru that incumbent presidents have misused their power.