Updates from the BBC live feed:
US says intelligence shows Hamas has base under Al-Shifa
US National Security Council spokesman John Kirby says the US has intelligence that Hamas has a command centre under Al-Shifa Hospital in Gaza City.
Kirby told reporters the intelligence shows that "Hamas and Palestinian Islamic Jihad use some hospitals in the Gaza Strip, including Al-Shifa, and tunnels underneath them to conceal and support their military operations and to hold hostages".
He said the groups have stored weapons under Al-Shifa and are "prepared to respond to an Israeli military operation against that facility".
Kirby added: "We do not support striking a hospital from the air and we do not want to see a firefight in the hospital where innocent people, helpless people, sick people are simply trying to get the medical care that they deserve, not to be caught in a crossfire. Hospitals and patients must be protected.
He said this points out how "challenging the military operation is. Hamas has deeply embedded itself within the civilian population. Israel has now an added burden given the way Hamas operates".
Finally, Kirby said that Hamass actions "do not lessen Israels responsibilities to protect civilians in Gaza" - and stated that the US is maintaining "active conversation" with the Israeli government about that.