Namangan is unnervingly still. The call to prayer should be sounding from a host of mosques in this holy month of Ramadan, but there is silence.

The authorities have ordered all loudspeakers to be switched off. Militia searched our car 10 times on the road into town.

The curfew is in force strictly, right across the valley. Secret policemen are everywhere.

The hotel is full of agents. They watch the comings and goings of the mosques, and listen to conversations.

They are meant to be unearthing what lay behind the murder of four policemen, one of whom was beheaded. Many people in Namangan think the killings were a mafia-type vendetta, but the authorities blame a mysterious Islamic sect.

Namangan is famous for its piety, and has very much its own character. Some women still wear the long, dark veil seen in central Asia in the Middle Ages.

This is not the kind of image the tough, secular government wants for Uzbekistan. It's terrified of the power of the mosque, and opposed to the partly Islamic government being drawn up across the border in Tajikistan.

The Uzbeks have taken every measure to control religion at home. But there are signs of new pressure.