The Palestinian Authority (PA) says it is pulling its staff out of the Rafah border crossing between the Gaza Strip and Egypt, effectively closing the main exit point from the coastal territory.
A statement accused the militant group Hamas, which controls Gaza, of harassing and detaining PA employees.
Hamas said the move amounted to “additional sanctions” on the people of Gaza by the West Bank-based PA.
The PA took control of the crossing in 2017 as part of a reconciliation deal.
The agreement, which was brokered by Egypt, aimed to end a decade-long split between Hamas and its secular rival, Fatah, which dominates the PA. But a dispute over power-sharing has hindered its implementation.
Palestinians in Gaza and the occupied West Bank have been ruled separately since deadly clashes between Hamas and Fatah broke out in 2007.
Hamas won parliamentary elections in the occupied territories the previous year, and reinforced its power in Gaza after ousting Fatah from the enclave.
Israel and Egypt tightened their blockades of Gaza in response to the Hamas takeover and in an attempt to prevent attacks by Palestinian militants.
The PA’s civil affairs authority said on Sunday that it had sent staff to the Rafah crossing 14 months ago “to alleviate the suffering of the siege”, but that since their arrival Hamas had been “obstructing” their work.
“After Hamas’s insistence on bolstering division… and the questioning, detention and suppression of our employees, we have become convinced it is useless to maintain our presence there,” it said.
A Hamas spokesman told AFP news agency that the move constituted a “new step” by President Mahmoud Abbas, the leader of Fatah, “in separating the West Bank from the Gaza Strip”.
The Palestinian Maan news agency reported that the Hamas-run interior ministry had assumed responsibility for managing the crossing on Monday, but it was not clear whether Egypt would allow it to continue operating.
The announcement about Rafah came amid rising tensions between the factions.
Fatah said Hamas-led security forces had detained hundreds of its supporters in Gaza ahead of a rally marking the 54th anniversary of its founding, while Hamas said dozens of its supporters had been held by PA forces in the West Bank.
And on Friday, the Gaza offices of the PA-funded Palestinian Broadcasting Corporation in Gaza were attacked and ransacked by armed men.
In a separate development on Monday, the Israeli military said it had struck a Hamas militant camp in northern Gaza after a rocket was fired towards southern Israel. There were no reported injuries on either side.