An Australian doctor treating patients in northern Gaza has described the conditions he's working in as catastrophic. 

Dr Wajid Khan says he has "lost a lot of patients ... with blast injuries" in the past two days with medication for pain relief in short supply as Israel continues its air strikes in the strip.

The Israeli military says its forces have resumed ground operations in the central and southern Gaza Strip, as a second day of air strikes killed dozens of Palestinians, according to local health workers.

Israel's Prime Minister Benjamin Netanyahu says the latest air strikes in Gaza won't stop until all Israeli hostages are released and the militant group Hamas is destroyed.

Meanwhile, Ukrainian President Volodymyr Zelenskyy has described a phone call with US President Donald Trump overnight as "positive", "frank", and "very substantive".

It's the first conversation between the two leaders since last month's tense Oval Office meeting and comes a day after Mr Trump's 90-minute phone call with his Russian counterpart, Vladimir Putin. 

And the Trump administration has released tens of thousands of pages of previously unseen documents relating to the assassination of former President John F Kennedy in 1963.

Donald Trump had made a campaign promise to release the files — containing around 63,000 pages — despite persistent refusals from previous presidents including Joe Biden and Barack Obama.

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