While millions around the world marked the end of the holy month of Ramadan last week, a cloud hung over celebrations in Japan. Muslims here say they feel they are constantly under the ever-watchful eyes of the police.

Otsuka Mosque in Tokyo usually hosts around a few dozen Muslims for morning prayers, but hundreds packed the small prayer rooms last Wednesday on Eid al-Fitr, the holiday that signals the end of Ramadan.

"We had to hold the prayers four separate times so all the people lining up could fit in," explains Haroon Qureshi, secretary-general of the mosque's Japan Islamic Trust organization. "There must have been 1,000 people waiting to pray."