A black-and-whte satellite image shows an overview of the Rafah border crossing between Egypt and the Gaza Strip in the southern Gaza Strip on Tuesday. Reuters

Russia said on Wednesday that it saw no prospect so far for a peace settlement in Gaza or the wider Middle East.

Israel on Wednesday said it had reopened the Kerem Shalom border crossing to humanitarian aid for Gaza, four days after closing it in response to a rocket attack that killed four soldiers.

It said the Erez border crossing between Israel and northern Gaza was also open for aid deliveries into the Palestinian territory, for the first time since the war broke out.

The United Nations and Israel's staunchest ally the United States both condemned the closure of the crossings which are a lifeline for civilians facing looming famine.

All sides present at truce talks

Talks aimed at agreeing the terms of a truce in the seven-month war between Israel and Hamas in Gaza resumed in Cairo on Wednesday "with all sides present", Egyptian media reported.

"Truce negotiations have resumed in Cairo today with all sides present," Egypt's AlQahera News, which is close to the intelligence services, reported, citing a "senior official" it did not identify.

Russia said on Wednesday that it saw no prospect so far for a peace settlement in Gaza or the wider Middle East, and said Israel's operation in Rafah was escalating the conflict.

This handout picture shows Israeli forces in Rafah in the southern Gaza Strip. AFP

Russian Foreign Ministry Spokeswoman Maria Zakharova said the conflict had caused a "humanitarian catastrophe".

African Union slams moves

The African Union condemned on Wednesday the Israeli military's moves into southern Gaza's Rafah, calling for the international community to stop "this deadly escalation" of the war.

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."

The Israeli push into Rafah, which is packed with displaced civilians, came as negotiators and mediators met in Cairo to try to hammer out a truce in the seven-month war between Israel and the militant group Hamas.

Agencies