Two Egyptians have been killed and two injured in an apparent attack on a Coptic church building near the Libyan city of Misrata, officials say.
A Misrata city council official told the BBC that there had been an explosion at the building as the four victims were eating lunch there.
It is not clear who was behind the blast in the small town of Dafiniyah.
There were conflicting reports as to whether it happened on Saturday or Sunday.
The Misrata council official told the BBC that home-made dynamite used for fishing was found on the site of the explosion.
The Egyptian government has requested more security at the church, Egypt's Mena news agency reported.
"Egypt is requesting an investigation into the circumstances of the operation and for those responsible to be put on trial," it quoted Egyptian Foreign Minister Mohammed Kamel Amr as saying.
The church in Dafiniyah, just outside Misrata, is frequented by Egyptians.
Libya has a small Christian population composed mainly of foreigners. These include migrant workers from Egypt, where Coptic Christians are the biggest religious minority.
The Libyan government has been struggling to impose its authority and provide security in the aftermath of the conflict that toppled Muammar Gaddafi last year.
Recently, there has been a series of attacks against diplomatic missions and aid agencies, including a deadly assault on the US embassy in the eastern city of Benghazi in September.
There have also been attacks in Libya against Sufi shrines and mosques that witnesses say were carried out by militant Islamists.