The White House has condemned Wednesday's deadly shelling of a UN shelter in southern Gaza, reiterating its position that the Israeli occupation has a "responsibility to protect civilians."

The Gaza director of the United Nations agency for Palestinian refugees (UNRWA) said earlier Wednesday that two tank shells had hit a building sheltering 800 people in the city of Khan Younis, with reports that nine people had been martyred and 75 more were injured.

"We are gravely concerned by reports today of strikes hitting a UNRWA facility -- with subsequent reports of fires in the building -- in a neighborhood in southern Gaza where more than 30,000 displaced Palestinians had reportedly been sheltering," a spokesperson for the White House's National Security Council, Adrienne Watson, said in a statement, failing to blame the Israeli occupation for the shelling.

She called the loss of innocent life a tragedy and the deaths and injuries of children during the three-month war "heartbreaking", while Washington continues to provide "Tel Aviv" with military and diplomatic support to pursue massacres in Gaza and the occupied West Bank.

Reiterating the United States' unwavering support for the Israeli occupation's so-called "right to self-defense," Watson stressed that "Israel retains a responsibility to protect civilians, including, humanitarian personnel and sites."

The US State Department also deplored the attacks on the UN facility and stressed that humanitarian workers must be protected so that they can keep providing lifesaving assistance to civilians.

On Tuesday, the Israeli occupation military said it had "encircled" Khan Younis, Gaza's main southern city which has become the epicenter of recent battles with the Palestinian Resistance.

The attack on the shelter in southern Gaza's biggest city sparked international condemnation, while the United Nations slammed a "blatant disregard" for the rules of war.

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