* FARC leader calls on Santos to help save peace process
* Colombian president says peace is saved through deals
* Rebels bombed key oil pipeline twice this week
Colombia's government will not hold back militarily or politically in its offensive against Marxist rebels, President Juan Manuel Santos said on Saturday, after FARC guerrillas said his hostile attitude was threatening peace negotiations.
Latin America's longest-running insurgency has heated up in recent weeks after a series of kidnappings and conflicts across the country, while government and rebel negotiators meet in Cuba to try to reach a deal to end the five-decades-old war.
Both sides traded barbs this week, with Santos saying rebels should compensate thousands of farmers who were forced to flee their lands, and FARC leader Timochenko charging that Santos' statements were hampering delicate talks in Havana.
"The gauge for the government is in Cuba. As we move forward (with the peace process) we are satisfied. If we do not move forward, we get up from the table," Santos said in a weekly address broadcast on local television.
"Here there is no truce of any kind, not militarily, not judicial, not even verbal," he said.
The Revolutionary Armed Forces of Colombia, known as the FARC, has repeatedly called for a bilateral ceasefire, which the government flatly rejects. The FARC ended a two-month unilateral ceasefire on Jan. 20.
Since then, fighting has heated up, especially in southern Colombia, where guerrillas maintain a strong presence, and which is a key route for smuggling drugs.
The war of words is also simmering.
In a letter published on Friday, Timochenko called on Santos to help "save" the peace process.
"Peace is saved with concrete agreements, and not with letters and pronouncements," Santos retorted on Saturday.
Guerrillas have stepped up attacks against the oil and mining sectors, key industries for economic growth that have attracted huge foreign investment inflows since a 2002 military offensive pushed rebels into more remote hideouts.
FARC rebels dynamited the Cano Limon-Coveñas oil pipeline twice this week, once on Wednesday and again on Friday, in the Norte de Santander province, according to military officials and the state-run oil company Ecopetrol.
The attacks against the 780-km (485-mile) line, which transports 80,000 barrels of oil per day, caused fires and spilt crude into the Catatumbo river, the company said.
Various peace efforts in Colombia since the 1980s have brought mixed success, with some smaller armed groups demobilizing. But the FARC, Latin America's biggest rebel group, has pressed on, funded in large part by drug trafficking.
The guerrillas were widely seen to have used previous negotiations to re-arm and rebuild their ranks. Right-wing elements linked to Colombia's political establishment were also accused of undermining talks.
During the conflict millions of Colombia's rural poor have been forced from their homes by FARC rebels and right-wing paramilitary groups who later used the land to fund their forces.
The FARC considers itself the representative of Colombian peasants in their struggles with big landlords and foreign mining and oil companies.
Since coming to power in 2010, Santos' government has pushed through reforms such as the restitution of land to displaced peasants. The move was seen as paving the way for peace talks with the rebels, which began late last year.
"The Colombian state, the fundamental perpetrator of the conflict, cannot pretend to be judge and jury in the processes that seek to clarify truth and restitute victims," the rebels said in a statement in Cuba on Saturday.
The guerrilla group asked for a high-level commission made up of FARC members, the national government, guilds and social groups to investigate displacement in Colombia.
It also wanted "the guarantees necessary so that in Colombia, in safe conditions, (the committee) can check and verify the real situation of the properties that are said to have been taken by us."