Twelve people have died in twin attacks on Coptic Christians in the Helwan area south of Cairo, officials say.
Ten people died when gunmen tried to storm a church south of Cairo, but were intercepted by police.
About an hour later, a Coptic-owned shop in the same area was attacked, leaving two dead.
More than 100 Christians have been killed in Egypt in the past year – most attacks claimed by the local branch of the so-called Islamic State group.
Security forces have put checkpoints in place around the capital in response to the attacks.
They announced plans earlier this week to protect festivities around the New Year and Coptic Christmas. They include the deployment of rapid-reaction forces and jamming equipment.