Colombian rebels killed a state governor, a former defense minister and eight other hostages Monday as army troops tried to rescue them, President Alvaro Uribe (search) said.

The captives, including Gov. Guillermo Gaviria and former Defense Minister Gilberto Echeverri, were killed as the soldiers approached the rebel camp where they were being held, according to a presidential statement.

One hostage escaped unharmed and two others survived but were wounded. No rebels were captured or killed in the failed rescue operation.

A grim Uribe addressed the nation late Monday night, calling on Colombians to support him in the fight against the rebels.

"In this moment of pain, Colombia cannot surrender," he said. "Now, we have to fortify our decision to defeat terrorism."

Uribe, visibly choked up, said he had personally called Echeverri's family.

"For me, it is a very hard blow that Gilberto Echeverri died in this way while I was president," he said. "That call I made painfully."

Gaviria and Echeverri were kidnapped just over a year ago as they led a peace march.

After military commanders explained the rescue operation to the nation, the president's office presented an interview with one of the survivors who said that a rebel commander ordered the hostages killed.

"A rebel known as the Paisa ... gave the order not to leave any survivors," said Antinor Hernandez, from a hospital bed where he was recovering from injuries suffered in the rescue attempt.

A member of the Navy, Hernandez was kidnapped three and a half years ago, a presidential spokesman said.

Hernandez said there was never any crossfire between rebels and government troops.

Medellin radio stations broadcast a communique allegedly received from the Revolutionary Armed Forces of Colombia, known as the FARC (search), blaming the government for the deaths.

Earlier reports indicated the bodies had been found along with eight other apparent kidnap victims in a common grave in the jungle-covered mountains of Antioquia state, but military officials said the bodies had been left where they were killed.

Uribe made an emergency trip to Medellin, Antioquia's state capital and Colombia's second-largest city, after hearing unconfirmed reports that the men had been killed by their rebel captors.

The killings outraged Colombians long inured to a four-decade civil war, and led to renewed calls for the government to exchange imprisoned rebels for hostages held by the guerrillas.

"I am truly shaken," said former President Ernesto Samper (search), under whom Echeverri served as defense minister. "It seems to me that we've reached intolerable levels of violence."

Officials at the Colombian Attorney General's office confirmed that 10 bodies had been discovered in a common grave near the village of Urrao, 30 miles west of Medellin. It was unclear when the victims died.

New York-based Human Rights Watch (search) blamed the FARC.

"The onus for these death lays squarely on guerrillas, who held them hostage for over a year," said Jose Miguel Vivanco, a director of the organization.

Uribe, who previously served as governor of the Antioquia province in the mid-1990s, has taken a hard line against leftist rebels who have fought a succession of elected governments in this South American country.

He has been under intense pressure from the Catholic Church and relatives of political prisoners to exchange rebels in government jails for the hostages.

Uribe has said he would only consider an agreement if it was brokered by the United Nations and included the freedom of all hostages, not just the political hostages.

Gaviria and Echeverri were kidnapped on April 21, 2002, as they led hundreds of peace marchers from Medellin to the village of Caicedo to meet with the FARC commanders. The village had declared itself a nonviolent community, but guerrillas had confronted residents.

As the march approached Caicedo, a small group of armed rebels intercepted the march leaders and told them rebel commanders in the hills wanted to question them. The rebels allowed other marchers to walk away.

The FARC also is holding 12 state lawmakers they kidnapped last year in a raid on state legislature, as well as dozens of soldiers and police officers and three American contractors captured in February when their plane went down in rebel territory.

The rebels are fighting the government and illegal right-wing paramilitary forces in a conflict that kills some 3,500 people annually, mostly civilians.

Despite the killings of Gaviria and Echeverri, some maintained hope that all chances for a future peace process in Colombia were not lost.

"We can't lose confidence that one day Colombia will emerge from this nightmare and this pain," said the Vatican's representative in Colombia, Benglamino Stella.