Security was ramped up at churches in parts of Nigeria amid fears of more attacks from Boko Haram.

The Islamist militant group launched bombing attacks over the first three weekends of June as Christians gathered for Sunday services.

At least 10 people were killed in a suicide bomb attack on a church in Bauchi in the first weekend of June. The following weekend, at least seven people were killed in attacks on churches in Jos and Biu.

Last weekend, at least 21 people were killed in three suicide bomb attacks on churches in Zaria and Kaduna.

Christian Solidarity Worldwide launched a month of prayer for Christians in Nigeria last week after Boko Haram warned of more attacks and its desire to make June “its bloodiest month yet”.

AllAfrica.com reports that there was a heavy security presence in Kaduna, Kano, Jos and Abuja, with random searches being conducted on cars and motorcycles.

Vehicles were prevented from entering church premises and the areas surrounding the churches were patrolled by plain-clothed security personnel.

However, the news agency reports that many Christians chose to stay at home out of fear of more attacks.

The attacks have occurred largely in Nigeria’s predominantly Muslim north, where Boko Haram has declared its intention to implement Sharia law.