Analysts said the unprecedented nature of the Hamas assault could make any diplomatic efforts fruitless
Israel said it has called up 300,000 army reservists as it battles to dislodge holdout Hamas fighters. Image/AFP AFP News

The 20-year-old British man, Nathaniel Young, who was killed in the Hamas militant group's attack on Israel on Saturday, was laid to rest on Monday in Jerusalem.

His final rites were carried out by people who were not known to him. Hundreds of people gathered to pay their last respects to the young soldier.

"He didn't have any family here; he was alone. Maybe he had family in the UK, but here he had nobody, and his soul should not go alone. We came to thank him and say goodbye," Michail Levinson, one of the mourners, told The Guardian.

Young was a corporal in the Israel Defense Forces. He had been listed as living in Tel Aviv and a member of the army's 13th Battalion. He came to Israel from London to serve in the military.

His family confirmed his death in a statement posted on Facebook. "We are heartbroken to share that our little brother Nathanel Young was tragically killed on the Gaza border...," it read.

Another 26-year-old British man went missing after Saturday's surprise attack by Palestinian militants. He was one of the soldiers who were providing security at a music festival near the Gaza border.

The UK Foreign Office has warned people against travelling to Israel and the Occupied Palestinian Territories (OPTs).

"The Israeli government has declared a state of emergency across the whole country. International borders (air and land) in Israel and the OPTs could close at short notice. You should check with your airlines and travel insurers before travelling. You are advised to consult Israeli Home Front Command for more information: or call 104 if you are in Israel," read FCDO's advisory.

After the unprecedented attack from Hamas, a pro-Palestinian militant organisation that has dominated Gaza since 2005, Israel formally declared war on Gaza and warned Palestinians to evacuate the area.

"Our enemy will pay a price the type of which it has never known," Israeli Prime Minister Benjamin Netanyahu said about Saturday's attacks. "We are in a war, and we will win it," he added.

The massive coordinated assault by Hamas militants and the retaliatory violence by Israel has resulted in the deaths of at least 3,000 people in Gaza and Israel combined.

The latest violent conflict between Israel and Hamas has been going on for five days now. The Israeli Defense Force has claimed that they have recaptured Gaza border areas from Hamas.

The United States has already begun supplying ammunition to Israel. US Secretary of State Antony Blinken is also expected to visit Israel on Thursday to "reaffirm US solidarity with the government and people of Israel". The UK has also extended "unequivocal" support to Israel.