Latest: Islamic State claim attacks that killed 37 in Egyptian churches

Latest: IS has claimed the attacks via its Aamaq news agency, after having recently warned that it would step up attacks on Egypt's Christians.

What we know so far:

• At least 25 people have been killed and 70 wounded after a bomb exploded in a church in Tanta;
• At least 11 people have been killed and 35 wounded in a second blast at a church in Alexandria;
• Islamic State has claimed the attacks;
• The attacks come just weeks before Pope Francis is due to visit Egypt.