The Israeli military says it has killed about 9,000 combatants of the Islamic group Hamas in the Gaza Strip in the 100 days of fighting in the Palestinian territory.

The military said on Sunday that it has also killed more than 70 Hamas commanders.

Attacks continued on Monday, with local media reporting that 33 people died in the southern city of Khan Younis.

Meanwhile, Hamas released footage that purportedly shows three of the hostages it is holding in Gaza.

The group did not say when the video was taken, but argued that many of the hostages are believed to have died recently, and the remaining ones are facing imminent danger to their lives.

Hamas reiterated that it won't hold negotiations on their release while Israel continues its military offensive.

World Health Organization Director-General Tedros Adhanom Ghebreyesus posted a statement on social media on the 100th day of the conflict.

He said, "Following over 300 attacks on health and continuous lack of safe access to critical aid, the majority of hospital in the Strip have stopped working. The 15 facilities that are still working can only provide limited health care."

He also said patients are "facing avoidable amputations due to the health system's destruction. Those with serious chronic conditions are dying due to the lack of care."