The car bomb exploded as worshippers left a New Year's Eve service
A car bomb explosion outside a church in the north Egyptian city of Alexandria has killed at least 21 people and injured 43, officials say.

The blast hit worshippers as they left a new year's service at the al-Qidiseen church shortly after midnight.

Sectarian tensions have recently been on the rise in Egypt.

After the explosion, angry Coptic Christians clashed with police and local Muslims, reportedly throwing stones and targeting a nearby mosque.

Protesters went into the mosque, throwing books out onto the street, the Associated Press news agency reported. The mosque had also been damaged by the car bomb.

A large contingent of police rushed to the scene and used tear gas to disperse the crowd. The situation is reported to be under control now, but BBC reporter Assad Sawey says it is still very tense.

It is not known who carried out the attack.

The casualties included eight injured Muslims, the health ministry said.

Our correspondent says relatives are being denied access to the victims' bodies at the morgue and it is not clear when they will be buried.

Christians in the Coptic Orthodox Church make up about 10% of Egypt's population, most of whom are Muslims.