By Helen Murphy

BOGOTA (Reuters) - Colombian government peace talks with leftist guerrillas to try and end Latin America's longest-running insurgency will begin next month in Norway before moving to Cuba, President Juan Manuel Santos said on Tuesday.

Unlike past failed negotiations with the Revolutionary Armed Forces of Colombia (FARC) guerrillas, however, there will be no ceasefire this time, Santos said in a national TV address.

"I ask the Colombian people for patience and strength," Santos said, announcing the talks would start in the first half of October. "There's no doubt it's time to turn the page."

While Colombians are hopeful Santos will succeed, he faces a monumental task to reach peace with the FARC, which has holed up in Colombia's jungle territory since 1964 and imposed tough demands in past peace negotiations.

In a video message broadcast to journalists in Cuba, the FARC's bearded leader Rodrigo Londono, known by his war alias Timochenko, urged a "civilized dialogue" to end the bloodshed.

Santos, 61, who is at the mid-point of a four-year term, had repeatedly said he would consider talks with the FARC only if he was certain the drug-funded group would negotiate in good faith.

"There are people like me that don't know a single day of peace," said Santos, son of one of Colombia's most influential families that founded the daily newspaper El Tiempo. "We have to take the dream of living in peace and make it a reality."

Established in 1964 as a communist-inspired peasant army but later coming to depend on drug-trafficking, the FARC comes to peace talks this time from a severely weakened position.

Battered by a decade-long U.S.-backed Colombian military offensive, the rebels have lost as much as half their fighting force, reducing their ability to launch major attacks on the government. The rebels number around 8,000 fighters now.

Still, they are by no means spent and in recent months have stepped up assaults on economic infrastructure like oil and mining installations in a bid, some analysts say, to come to the negotiating table from a position of relative strength.

INTERNATIONAL SUPPORT

Santos said Venezuela and Chile would support the talks that would take place "without interruptions," although they would end if there were no advances.

Critics of the peace process are worried the rebels could use the time to build strength and prolong the war.

Former President Alvaro Uribe, a constant critic of Santos who has accused him of pandering to "terrorists," described the talks as "grave."

"The government has arrived at this dialogue from a position of weakness and terrorism from a position of resurgent strength," said Uribe, who was once a close ally of Santos. "Security has deteriorated significantly in the last two years."

In the video shown in Cuba, Timochenko said Colombians deserved better than more years of conflict.

"How much death and destruction, how much pain and tears, how much useless bereavement and abuse, how many lives and smiles must be cut before we finally conclude that the end to this isn't conflict but civilized dialogue?" he said, dressed in an olive green uniform.

In 1999, former President Andres Pastrana ceded the FARC a safe haven the size of Switzerland to promote talks.

But the rebels took advantage of the breathing space to train fighters, build more than 25 airstrips to fly drug shipments and set up prison camps to hold its hostages.

Santos has been laying the groundwork for peace since he took office, creating a land reform that would help return land stolen by FARC and paramilitary groups.

He also pushed through a constitutional reform that set the legal basis for eventual peace with the rebels. The reform prohibits guerrilla leaders accused of crimes against humanity from holding political office.

Among negotiating points, Santos said the two sides will discuss rural development and improved access to land, the integration of the rebels into civil society, the drugs industry and the rights of victims.

The choice of Norway and Cuba as venues, plus Venezuela and Chile as support countries, provide an ideological mix intended to make both sides feel comfortable with the process.

Norway is well known for its international mediation work, while Cuba and Venezuela are run by socialist governments with whom the FARC feel political affinity. Chile's conservative government is an ally of Bogota.

"It takes courage to seek peace," said Norway's Foreign Affairs Minister Jonas Gahr Store in a statement. "I would like to commend the parties for entering into a dialogue that could bring an end to the protracted armed conflict in Colombia."

(Additional reporting by Nelson Bocanegra; Editing by Andrew Cawthorne, Kieran Murray and Cynthia Osterman)