The head of the Methodist Church in Nigeria, Samuel Kanu, has been abducted along with two other priests on their way back from a church event.

The men were travelling on a major highway on Sunday in the south-eastern state of Abia when they were kidnapped, local police told the BBC.

It is not clear who is responsible, but separatist groups frequently carry out abductions in the region.

Police say they have launched a rescue mission to find the clerics.

Kidnappings, often for ransom, are common in many parts of Nigeria.

There has also been a resurgence of attacks by armed gangs, including Islamist militant groups in the north, as the country prepares for a general election next year.

Much of the unrest in Nigeria's south-east region stems from separatists who are demanding a breakaway state.

The government blames the Indigenous People of Biafra (Ipob) movement for many attacks in the region, which Ipob denies. But the group continues to enforce sit-at-home orders on Mondays, which are usually preceded by attacks on Sunday evenings to scare people into complying.

However it is not known who abducted the clergymen on Sunday, and a number of recent violent attacks in the country remain unsolved.

Recently a local MP was kidnapped by unknown gunmen. His headless body was later found.

In April, a male and a female soldier who hoped to get married were beheaded when they travelled to the region to inform their relatives about their planned wedding.

In a separate incident on Sunday morning, two people were abducted when gunmen entered their home in Lafia, Nasarawa state, near the capital Abuja. One person was shot dead during the attack.