(Adds details on attack)

BOGOTA, Feb 9 (Reuters) - Colombia's FARC guerrillas are calling for a prisoner exchange with the government to free more hostages held for as long as a decade after they handed over six captives last week.

FARC leaders freed four members of the armed forces and two politicians to the Red Cross, and are insisting on a broader deal to release jailed guerrilla fighters in exchange for more hostages held in the rebels' jungle camps.

"We hope this gesture will open the way for an exchange agreement that is blocked by the government," the FARC's leadership said in a statement published on the website of a left-wing senator who brokered the recent releases.

"The whole of Colombia wants to be able to celebrate a bilateral agreement to free prisoners held both in the regime's jails and in the mountains," the brief statement said.

News of the statement came as six soldiers were killed and four more were wounded in a guerrilla attack on a military patrol in a southeastern province, the army said on Monday.

The Revolutionary Armed Forces of Colombia, or FARC, has long demanded a prisoner exchange but President Alvaro Uribe and rebel leaders are far apart over the terms of any deal.

Latin America's longest-running insurgency, the rebels have been severely weakened by Uribe's U.S.-backed security offensive, and violence and kidnapping from the four-decade-old conflict has eased since he became president six years ago.

But rebels remain a force in rural areas. More than 370 members of the armed forces were killed last year in combat with FARC and other armed groups, according to the defense ministry.

The FARC has little support and is branded a drug-trafficking terrorist group by the United States and European governments. Last week's releases appear to be an attempt by the rebels to regain the political initiative after a year of military setbacks.

Guerrillas still hold 22 soldiers and police officers in jungle camps and say they want to swap them for jailed guerrilla fighters in a humanitarian prisoner exchange. They are also holding hundreds more captives for extortion.

The FARC also wants Uribe to demilitarize a rural zone roughly the size of New York City in southern Colombia to help facilitate peace talks. He dismisses that option but has offered a smaller safe haven under international observation.

Uribe's government has also sought to fracture the guerrillas by offering amnesty to fighters who come in from the jungles with hostages they are holding. The FARC's founder and two top commanders died last year, and their ranks were further sapped by desertions. (Reporting by Patrick Markey in Bogota; Editing by Kieran Murray)

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