Israel bombed the Gaza city of Rafah and launched a ground incursion there, interrupting humanitarian aid deliveries, despite international objections.
Tanks were sent into Rafah and the nearby crossing into Egypt was seized.
The White House condemned the move and paused a shipment of bombs due to concerns over Israel's Rafah plans.
Later, Israel reopened two major aid crossings into Gaza, Kerem Shalom and Erez.
The UN agency for Palestinian refugees reported that the Kerem Shalom crossing, which Israel closed following a rocket attack that killed four soldiers, remained shut.
The closure came after a night of heavy Israeli strikes and shelling in Gaza.
Footage from AFPTV showed Palestinians pulling survivors from the rubble of a building in Rafah.
Russia expressed concern over the escalating conflict in Gaza, blaming Israel's military incursion into Rafah for the escalation and seeing no prospect for peace in Gaza or the Middle East at this time.
Approximately 1.5 million Palestinian civilians are living in the Gaza Strip, and there is a demand for strict adherence to international humanitarian law.
However, finding a lasting settlement in the Middle East is far from being achieved, and the situation in Gaza is worsening daily.
Residents of Rafah, such as Muhanad Ahmad Qishta, live in fear as the Israeli army indisiscriminately fires artillery shells.
The displacement of people is also increasing as areas claimed to be safe are being bombed.
The Gaza war began on October 7, 2021, when Hamas launched an unprecedented attack on Israel, resulting in over 1,170 deaths, mostly civilians.
In response, Israel vowed to crush Hamas and launched a military offensive, resulting in at least 34,789 deaths, mostly women and children, in Gaza according to the Hamas-run territory's health ministry.
Militants took around 250 people hostage, of whom Israel estimates 128 remain in Gaza, including 36 believed to be dead.
Ceasefire talks resumed in Cairo on Wednesday with all parties present, and a senior Hamas official described the negotiations as "decisive." An unnamed official from the Palestinian resistance reiterated their commitment to their people's rights and refused to back down in ongoing negotiations with Israel.
Previously, the official had issued a warning that this would be Israel's last chance to free remaining hostages held by militants.
Mediators have been unable to negotiate a new truce since a ceasefire in November resulted in the release of 105 hostages, including some Israelis in exchange for Palestinian prisoners held by Israel.