The fiery explosion of a homemade bomb killed a man in downtown Santiago on Thursday, officials said, adding to a string of blasts in Chile's capital.

Prosecutor Claudio Orellana initially said the man identified as Guillermo Landskron Silva had been handling the bomb when it exploded at about 1 a.m., but he later opened the possibility that he was a bystander. Witnesses posted online photos of the man in flames before he was taken to an emergency clinic where he died.

Doctors at the clinic said the man was gravely injured as well as burned. The coroner's office said he was 29 years old.

Officials say anarchist cells have planted some 200 bombs around Santiago over the past decade, and 30 so far this year. The only other fatality was also a man believed to be planting an explosive.

President Michelle Bachelet on Thursday described the bombings as "terrorist acts, but isolated."

The explosion comes two days after three alleged anarchists appeared in court and were ordered held on suspicion of planting at least four bombs, including one that injured 14 people at a shopping area near a subway stop this month.

Interior Minister Rodrigo Penailillo said that the design of new bomb appears to differ with that used in the subway blast.