One of three mail bombs sent to Indonesians blamed for "sins against Islam" wounded four people when police detonated it, a new threat coming as religious intolerance rises in the world's most populous Muslim country.
The bomb that exploded was addressed to Ulil Abshar Abdalla, the founder of the US-funded Islamic Liberal Network, which has long promoted a tolerant, open form of the faith through radio shows, the internet, discussion groups and publications.
The low-intensity devices delivered on Tuesday were placed in a hole carved into a heavy book titled "They should be killed for their sins against Islam and the Muslims".
A note with the bomb asked Abdalla, who was not in his office at the time, to name those who should top the "hit list."
The explosion wounded four people, including the policeman who lost his left hand trying to defuse the device.
"This is clearly a terror attack," said Anton Bachrul Alam, spokesman for the national police, after video of the officer's attempt was aired on local television. "We're still investigating to see who was behind this," he added.
National police spokesman Col Boy Rafly Amar said the devices sent to a former anti-terror chief and a third person did not explode.
Hard-liners seeking to carve out an Islamic state in the secular nation of 237 million have in recent months targeted Christians and other minorities, sometimes beating people with bamboo sticks and machetes.
Indonesia, home to more than 210 million mostly moderate Muslims, has been hit by a string of terrorist attacks blamed on the al Qaida-linked militant group Jemaah Islamiyah since 2002, when suicide bombings on Bali island killed 202 people.
Many of those victims were foreign tourists. But a new terrorist cell discovered just over a year ago has shifted tactics, experts say, instead targeting the liberal Muslim leaders such as president Susilo Bambang Yudhoyono and his security forces.