Thousands of Palestinians began fleeing their homes and moving south after Israel’s military delivered sweeping evacuation orders for almost half of Gaza’s 2.3 million people earlier on Friday ahead of an expected ground offensive. The UN said it was told by the Israeli military that about 1.1 million Palestinians in northern Gaza should relocate to the enclave’s south within the next 24 hours. Hamas urged people to stay put and defy the Israeli military order to evacuate homes. Israeli airstrikes on convoys fleeing Gaza City killed 70 people, mostly women and children, the press office of Hamas said. Hamas said the cars were struck in three places as they headed south from Gaza City on Friday. Israel’s prime minister Benjamin Netanyahu vowed to “eradicate” Hamas and said Israel’s counteroffensive in Gaza “is just the beginning”. Netanyahu, in televised remarks on Friday, said Israel was striking at its enemies “with unprecedented might”. “Our enemies have only started paying the price,” he said. Israeli troops carried out local raids over the past day in the Gaza Strip, searching for hostages and collecting evidence to find people taken by Hamas, the Israel Defence Forces said on Friday. US secretary of state, Antony Blinken, has urged Israel to take every possible precaution to avoid civilian casualties in Gaza as he called for the establishment in the territory of safe zones where shelter, food, water and medical supplies can be provided. “We have urged the Israelis to use every possible precaution to avoid harm to civilians,” he said. The UN’s secretary general, António Guterres, said the Israeli military’s evacuation order is “extremely dangerous – and in some cases, simply not possible”. The World Health Organization (WHO) said asking vulnerable patients to evacuate hospitals in Gaza amounted to a “death sentence”. Amnesty International said Israel’s evacuation order “cannot be considered an effective warning” and called for it to be rescinded immediately. At least 1,900 Palestinians have been killed in Gaza from Israeli strikes, including 614 children and 370 women, according to Gaza’s health ministry on Friday. At least 16 Palestinians were shot and killed in the West Bank over the course of the day, the Palestinian health ministry said. A journalist has been killed and six others injured after an Israeli shell landed in a gathering of international journalists covering clashes on the border in south Lebanon on Friday. Reuters confirmed that its videographer Issam Abdallah was killed. Meanwhile, the BBC said its journalists were assaulted and held at gunpoint after they were stopped by Israeli police in Tel Aviv. The US president, Joe Biden, said he had spoken with the families of Americans held by Hamas in Gaza, and that they were “going through agony” not knowing the fate of their loved ones. He also said he was making a priority of urgently addressing the humanitarian crisis in Gaza. The Israel Defence Forces have denied allegations by Human Rights Watch that they have used white phosphorus munitions in their military operations in Gaza and Lebanon. HRW said the use of such weapons put civilians at risk of serious and long-term injury. Palestinian groups have asked for the international criminal court to investigate. Tens of thousands of protesters rallied across the Middle East and in parts of Asia, Europe and the United States on Friday in support of Palestinians and condemnation of Israel. Elsewhere, Jewish communities in the US, France and other countries held rallies in solidarity with Israel after the Hamas attack from Gaza. British citizens trying to escape the war zone in Israel are having their repatriation flights repeatedly cancelled by the British government, while emergency flights arranged by US and Australian authorities are landing in the UK. Late on Friday it appeared the government had turned to using military transport to evacuate citizens.