A senior United Nations official has appealed to Israel to reverse its decision Friday to close its border with the Gaza Strip, following days of rocket attacks on Israel from the Palestinian territory. U.N. Chief of Humanitarian Affairs and Emergency Relief, John Holmes, says Gaza is already in crisis and closing the border will only deepen the emergency.  From U.N. headquarters in New York, VOA's Margaret Besheer has more.

Holmes told reporters that the situation in Gaza is very "serious" and "dire."

"I am deeply concerned by the closure this morning by Israel of all the crossing points between Gaza and Israel, because they are the lifeline for the delivery of humanitarian assistance and other goods to Gaza," he said.

Holmes says the U.N.'s Palestinian relief agency (UNRWA) is still operating relatively freely in Gaza, but he warned that access to medicine and food could become compromised if the closures continue beyond a few days. Holmes says virtually all of the 1.4 million people who live in Gaza depend on humanitarian assistance.

Israel says its decision to shut the border is intended to pressure the Islamic militant group Hamas, which controls the Gaza Strip, to stop firing rockets into Israel. Israeli military officials say more than 150 rockets have been fired into Israel since Tuesday, when an Israeli air and ground offensive killed 19 Palestinians, most of them militants.

But U.N. humanitarian chief Holmes criticized the border closure as "collective punishment."

"The Israeli reaction is not justified by those rocket attacks, even though it is caused by those rocket attacks," he added.  "That is the position we are clearly taking. That this kind of action against the people in Gaza cannot be justified even by those rocket attacks."

Holmes called on Hamas leaders to do what they can to stop the rocket attacks, saying it is their responsibility since they claim to be in control of Gaza.

The U.N. Human Rights Council will hold an emergency meeting Wednesday in Geneva to examine whether Israel is committing abuses in the Palestinian territories. Arab and Muslim countries requested the special one-day session.