BETHLEHEM (Ma'an) -- The commissioner-general of the UN agency for Palestinian refugees on Monday urged Israel to end its blockade of the Gaza Strip.

Fillipo Grandi, speaking to UNRWA's advisory commission, called for "the illegal Israeli blockade to be lifted in all its aspects - crossings, fishing zones, imports, exports - with proper guarantees given to and by all parties in respect of the security of all civilians," UNRWA said in a statement.

Grandi urged all parties to "seize the opportunity" provided by Wednesday's ceasefire in Gaza, calling the conflict a "tragic escalation."

"The greatest danger is to return to the status quo ante, and restore the prison-like conditions of Gaza. If this happened, it would be only a matter of time till violence resumed."

The crisis in Gaza was about the wider unresolved Israeli-Palestinian conflict, including the situation in East Jerusalem and the West Bank, Grandi said.

The UNRWA chief also briefed the commission about the situation for Palestinian refugees in Syria, saying that "concerns about the welfare of the half million Palestine refugees there have grown as they are increasingly affected by the conflict."

"UNRWA's strategy in Syria, as in Gaza," he said, "is to be there, maintain services and address the growing emergency needs as much as possible."

Wednesday's ceasefire deal ended eight days of fierce fighting that left some 170 Palestinians and six Israelis dead. Over 1,000 Palestinians were injured in the assault, with severe damage caused to civilian infrastructure in Gaza.