AU Commission chief Moussa Faki Mahamat "firmly condemns the extension of this war to the Rafah crossing", said a statement after Israeli tanks captured the key corridor for humanitarian aid into the besieged Palestinian territory.
Faki "expresses his extreme concern at the war undertaken by Israel in Gaza which results, at every moment, in massive deaths and systematic destruction of the conditions of human life", the statement said.
"He calls on the entire international community to effectively coordinate collective action to stop this deadly escalation."
Senior Hamas official Ismail Haniyeh announced on Monday that the Palestinian resistance movement accepted a Gaza ceasefire proposal put forward by Qatari and Egyptian mediators.
The Tel Aviv regime, however, insisted the deal didn't meet its core demands and rejected it, though it has said it will continue discussing the proposal.
The occupying regime started its incursion into Rafah on Monday and occupied and shut down the Rafah border crossing which is vital for the arrival of international aid from Egypt on Tuesday.
MNA