A human-caused famine is "tightening its grip" across the Gaza Strip, the head of the U.N. agency for Palestinian refugees warned on Wednesday as he accused Israel of blocking aid deliveries and seeking to end the U.N. Relief and Works Agency's activities in the enclave.

"Today, an insidious campaign to end UNRWA's operations is under way, with serious implications for international peace and security," UNRWA Commissioner-General Philippe Lazzarini told the 15-member U.N. Security Council.

UNRWA provides education, health and aid to millions of Palestinians in Gaza, the West Bank, Jordan, Syria and Lebanon.