(A Muslim woman holds a placard during a protest against the Ahmadi sect in Jakarta February 18, 2011. Indonesia's highest Islamic authority and many mass Islamic organisations in the most populous Muslim country consider Ahmadi "heretical" for believing that Mohammad was not Islam's final prophet. The placard reads, "Disband Ahmadi". REUTERS/Beawiharta)

(A protest against the Ahmadi sect in Jakarta February 18, 2011. The sign reads "Disband Ahmadiyah"/Beawiharta)

A small explosion has hit the Jakarta office of the Liberal Islamic Network, an Indonesian group that has defended the rights of minority Islamic  Ahmadi sect, a witness said. The explosion on Tuesday, which injured three people, comes a month after a mob beat to death three followers of the Ahmadi sect, considered heretical by mainstream Muslims.

Indonesia has won praise for largely defeating Islamic terror, but a recent spike in religious intolerance could heighten risk concerns for foreign investors counting on improved stability in Southeast Asia’s largest economy and the world’s most populous Muslim nation.

Ade Wahyudi, a manager at KBR68H radio that shares the office with the pluralist Liberal Islamic Network, said the office had called police to open a package that contained a book with wires sticking out of it. The police officer who opened the package was among the injured.

Rights activists and several parliamentarians said on Tuesday that military personnel in western Java island recently summoned Ahmadi leaders to identify Ahmadi followers in their area and asked them to return to mainstream Islam.