KABUL (Reuters) - An explosion went off in the Afghan capital, Kabul, on Thursday as crowds gathered to commemorate the 15th anniversary of the death of Ahmad Shah Masoud, a leader of the fight against Soviet forces in the 1980s and an enemy of the Taliban in the 1990s.

The blast, which came at a time of heightened concern over tensions between ethnic groups in Afghanistan, was attributed to a small bomb attached to a bicycle, Kabul police chief Abdul Rahman Rahimi said.

He said there were no casualties, but some media reported two people were wounded.

(Reporting by Josh Smith; Editing by Robert Birsel)