Egypt, Israel and the U.S. agreed to a ceasefire in southern Gaza beginning at 0600 GMT coinciding with the re-opening of the Rafah border crossing, two Egyptian security sources said on Monday.

The sources said the ceasefire would last for several hours but they were not clear on the exact duration. They also said the three countries had agreed that Rafah would be open until 1400 GMT on Monday as a one-day initial re-opening.

Rafah, which is on the border between Egypt's Sinai Peninsula and Hamas-governed Gaza, is the only crossing into the territory not controlled by Israel.

A security source and NGO source in Al-Arish said that aid trucks were still waiting there after 0600 GMT. Reuters images showed the trucks awaiting permission to make the trip to Rafah, which could take several hours.

Egypt has said that the crossing remained open from the Egyptian side in recent days, but was rendered inoperable due to Israeli bombardments on the Palestinian side.

Assistance that had come from several countries and organisations has been stalled in al-Arish awaiting an agreement on the delivery of aid and evacuation of foreign nationals from Gaza, which U.S. Secretary of State Blinken said had been achieved after a visit to Cairo.

Asked for confirmation, the Israeli military had no immediate comment.

Salama Marouf, head of the Hamas government media office, said they have received no confirmation from the Egyptian side about intentions to open the crossing.

The U.S. embassy in Israel said the situation at Rafah would be "fluid and unpredictable and it is unclear whether, or for how long, travelers will be permitted to transit the crossing."

It said citizens who felt safe enough to do so could move towards the crossing.