Israel's military is stepping up its offensive in southern Gaza, with its ground troops poised to push into the region's main city of Khan Younis.

The Israeli military on Monday said ground troops continued an offensive against Hamas militants in the enclave and that airstrikes hit about 200 Hamas positions there.

Israeli forces are focusing their operations on Khan Younis, Gaza's main southern city. Leaflets were dropped to urge residents to move further south for safety. Israeli personnel also closed a central road leading north out of the city, in an apparent bid to pave the way for the military advancement to the city.

Qatar-based satellite TV station Al Jazeera reported that Israeli tanks were spotted near Khan Younis.

Civilian casualties are rising. Footage from a hospital in Khan Younis showed a baby with an oxygen mask being brought in for treatment. The father said he and his family fled the northern city of Gaza to the south as instructed by the Israeli military, but his child was still injured. He said he is no longer sure what to do.

A Palestinian media outlet said at least 50 people were killed in an airstrike that hit two schools sheltering displaced people in Gaza City.

Health authorities in the Gaza Strip on Monday said 15,899 people have been killed and more than 42,000 injured since the conflict broke out on October 7. This means that nearly 700 new deaths were confirmed in the four-day period since Israel resumed combat operations on December 1.

Hamas said its militants destroyed 28 Israeli military vehicles and killed soldiers in the enclave. The Palestinian militant group also fired rockets toward Tel Aviv and other locations in Israel.

The Israeli move to intensify its offensive in southern Gaza, where many evacuees have been sheltering, is raising fears that civilian casualties in the region will continue to increase. The UN Relief and Works Agency for Palestine Refugees in the Near East said almost 1.9 million people, or more than 80 percent of the population of Gaza, have been displaced across the enclave since October 7.