Smugglers killed 15 Egyptian border guards near the frontier with Libya on Saturday.
The UN has warned that millions of people could be on the brink of starvation because violence.
The economic bloc announced travel bans and asset freezes on two military leaders.
The UN refugee agency needs $39 million for its nutrition support to refugees across the continent.
Ibrahim was sentenced to death last month for converting to Christianity from Islam.
AU official said the organisation is making progress towards a regional military force by end of 2015.