Authorities in Nigeria's north-western Kaduna state say the curfew imposed in the main city has been relaxed in some places for four hours to enable residents restock supplies.

But the round-the-clock curfew, for the nearly one million residents, remains in force in areas believed to be volatile.

The measure was put in place following protests on Sunday which degenerated into sectarian violence between Christian and Muslim groups who attacked each other with guns and machetes.

The violence had threatened to spread across the state.

At least 55 people died last week following the crisis which started in Kasuwan Magani.