Israeli forces are carrying out a "precise and targeted" military operation against Hamas "in a specific area" inside the Al Shifa Medical Complex in Gaza City.
The army said in a statement the operation is "based on intelligence information and operational necessities".
The IDF forces "include medical teams and Arabic speakers who have undergone specific training to prepare for this complex and sensitive environment, with the aim of not causing any harm to civilians who are used by Hamas as human shields".
The statement came shortly after the spokesman for the Hamas Ministry of Health in Gaza announced that Israel had informed officials that it would raid the Al-Shifa Hospital complex in the coming minutes.
On Tuesday, the US accused Hamas of running a "command and control center based from Al-Shifa Hospital."
Hamas has, however, denied militarising hospitals.
Medical officials in Gaza say more than 11,000 people are confirmed dead from Israeli strikes, around 40 per cent of them children, and countless others were trapped under rubble.
Israeli troops and tanks pushed on Saturday into parts of a congested northern Gaza Strip district that they had previously skirted in the more than seven-month-old war, killing and wounding dozens of Palestinians, medics and residents said.
Slovak Prime Minister Robert Fico is no longer in immediate danger but still in a serious condition, his deputy said on Sunday, four days after an assassination attempt that sent shockwaves through Europe.
At least 47 people have died after continued heavy rain and flooding in northern Afghanistan, an official said on Sunday, a day after a similar number were killed in a central province.
Russian airstrikes killed at least ten people and injured many others in a recreation area just outside Ukraine's northeastern city of Kharkiv on Sunday, local officials said.