QUITO, Ecuador (AP) _ President Leon Febres Cordero, kidnapped Friday by renegade paratroopers during a visit to the Taura air base, was freed more than 10 hours later when the government released the leader of an earlier revolt.

The Taura base is near the port city of Quayaquil, 170 miles southeast of Quito, the capital.

Radio reports said the president, Defense Minister Gen. Medardo Salazar and others seized by the paratroopers left the air base in a caravan of cars and went to the Guayaquil governor's mansion. People were reported gathered along the streets of the caravan's route and applauded as the cars passed.

The broadcasts said the president and his party were freed immediately after Gen. Frank Vargas Pazos, who had been jailed following an attempted revolt last March, arrived at the Taura base aboard a special government plane.

Local news reports earlier in the day said as many as 15 people might have been killed in a gun battle between paratroopers and presidential bodyguards, but Febres Cordero said in a telephone conversation that he and Salazar were uninjured.

Febres Cordero and other members of his party were seized at about 9:45 a.m. and freed at 8 p.m.

Vice President Blasco Penaherrera had anounced earlier that the troopers who seized the president had said, ''As soon as Gen. Vargas Pazos arrives at the Taura air base President Febres Cordero will be freed.''

Penaherrera, speaking late Friday in a national radio and television broadcast, said, ''I want to officially inform you that President Leon Febres Cordero and his party were freed tonight at the Taura air base.''

''General Vargas Pazos is now at the Taura base with the status of a free citizen,'' he said.

The vice president said Febres Cordero arrived in Guayaquil ''amid an enthusiastic demonstration by supporters of the constitutional government'' and then added: ''This is a moment that reaffirms our democracy. Let's retire to our homes and wait confidently for a better tomorrow.''

Earlier, speaking at an afternoon news conference at the presidential palace in Quito, Penaherrera made no mention of an earlier demand by the kidnappers that Febres Cordero be removed from office.

Vargas Pazos, 52, a former air force commander, had been held at the Epiclachima army base in the jungle east of Quito since the quashed revolt, awaiting trial on charges stemming from his actions.

Penaherrera said he spoke by telephone several times during the day with Febres Cordero, and the president ''under no circumstances will permit blood to be spilled again. Any armed encounter would be ominous and dangerous for the existence of the nation.''

Paratroopers surrounded Febres Cordero and Salazar during a ceremony at the Taura base and and there was a brief exchange of gunfire, reporters at the scene said.

They said up to 15 people were killed and four were wounded during the exchange of fire inside the base. There was no confirmation of those reports.

A number of presidential guards and three journalists also were taken hostage by the renegades, according to the witnesses.

Penaherrera said the order to free Vargas Pazos came from Febres Cordero. ''It is an order I am transmitting to Gen. Edison Garzon, and it is being carried out,'' he said.

Garzon is the highest army authority in the Quito district, which includes the army garrison where Vargas Pazos was detained.

After Penaherrera's news conference, Television Channel 2 showed film taken of Febres Cordero in the air base chapel where he was being held and the president told the station, ''I guarantee that my government ... will not take any disciplinary measures against those armed elements that took part in this action.''

The broadcast showed the president seated at a table writing a paper that the station said was written assurance that no reprisals would be taken against his captors.

Penaherrera said the kidnapping of Febres Cordero was ''lamentable and painful, but democracy will come out of it allright.''

From his captivity inside the Taura base, Febres Cordero spoke earlier with Radio Quito by telephone. He said both he and Salazar were uninjured.

Febres Cordero was allowed the telephone connection with Radio Quito after the leader of the insurrection, Col. Patricio Gonzalez, announced the demand for Vargas Pazos' release.

Vargas Pazos' wife, Miriam, later read to reporters in Quito a communique issued by the rebel troops.

''We demand the removal from office of President Leon Febres Cordero and the freedom of General Frank Vargas,'' it said.

Penaherrera had met in emergency session with the armed forces high command at the Defense Ministry.

A government communique distributed earlier by the Press Secretariat said that ''except for the attitude of a reduced group'' there was no other activity in the country challenging the established constitutional order.

''The executive branch, as well as the legislative and judicial branches and the institutions of the state maintain the firm decision to support the country's democratic system,'' it said.

In Washington, White House spokesman Albert Brashear said the U.S. government was ''deeply disturbed'' by the kidnapping of Febres Cordero and that it ''strongly urged'' his release.

The governments of several Latin American countries also issued statements condemning the insurrection.

Febres Cordero, a 55-year-old conservative, is one of the Reagan administration's staunchest allies in South America.

A reporter for Channel 10 television, Maria del Carmen de Aguayo, told viewers she witnessed the paratroopers' assault and the president's capture.

She said that shortly before the ceremony at Taura began, the elite forces surrounded Febres Cordero and Salaza and shots were exchanged.

She added that Febres Cordero and the defense minister were forced onto a bus and taken to the base chapel.

Febres Cordero, an engineer by profession and leader of the center-right Social Christian Party, began his four-year term in August 1984 after winning elections three months earlier.

Vargas Pazos last March demanded the firing of the then-defense minister, Gen. Luis Pineiros, who later resigned, and the army commander, accusing them of corruption. Febres Cordero sided with the two men and dismissed Vargas Pazos, who seized an air force base on the coast. When dismissed, Vargas Pazos was also chief of the Joint Forces Command.

After several days of talks he surrendered, but then rebelled, with the support of about 200 officers and troops at the Quito air base where he was being held. Vargas Pazos, who is described as charismatic and popular with his troops, charged that Febres Cordero had gone back on his word to try the defense minister and the army commander.

The president sent army troops and tanks into the base and retook it after a brief fight in which several soldiers were killed.

In September, Febres Cordero vetoed a congressional measure that would have granted amnesty to Vargas Pazos.

Vargas Pazos' rebellion was the most serious threat to the government since civilian rule returned to Ecuador in 1979 following seven years of military dictatorship.

Febres Cordero has emphasized private enterprise and pursued free market policies. He is one of the few Latin American leaders who has been outspoken in his backing for Washington's support for Nicaraguan rebels.