BOGOTA, Colombia - The legendary leader of Latin America's most powerful insurgency, Manuel "Sureshot" Marulanda, died of a heart attack in March, a senior guerrilla commander said yesterday.

Marulanda, believed to be 78, died "in the arms of his companion, surrounded by bodyguards and all the units who comprised his security," rebel commander Timoleon Jimenez said in a video broadcast by the Venezuela-based Telesur network. He said Marulanda's death followed a short illness, which he did not describe.

The Revolutionary Armed Forces of Colombia, or FARC, is now led by its chief ideologist, Alfonso Cano, Jimenez added.

"A great leader has marched on," said Jimenez, who is also known as Timochenko. Marulanda died on March 26, he said, without specifying where. Colombia's Defense Ministry, which first reported the death on Saturday, gave the same date.

Military officials said Marulanda's death had coincided with a series of bombings in the southern jungles where he was believed to be holed up.

Marulanda had led the peasant-based FARC since its 1964 inception and was "one of the figures who did the most damage to Colombia, who caused so many deaths," Interior Minister Carlos Holguin said, urging the nation to take comfort in his death.

Marulanda's death is a major blow to the FARC, the latest in a series of setbacks for the communist insurgents, whose defeat has been President Alvaro Uribe's main goal.

In March, guerrilla commander Raul Reyes and another member of the rebels' seven-man ruling body were killed, and last weekend a female leader well-regarded inside the group defected.