The US announced sanctions on Wednesday against a group of 10 Hamas members and the Palestinian militant organisation's financial network across Gaza, Sudan, Turkiye, Algeria and Qatar as it responds to the surprise attack on Israel that left more than 1,000 people dead or kidnapped.

President Joe Biden, who arrived in the Middle East late Tuesday to show support for Israel, has tried to tamp down tensions in the escalating war between Israel and Hamas, but those efforts have faced massive setbacks, including a deadly explosion at a Gaza hospital that killed about 500 people.

Targeted for Wednesday's sanctions action by the Treasury Department's Office of Foreign Assets Control are members who manage a Hamas investment portfolio, a Qatar-based financial facilitator with close ties to the Iranian regime, a key Hamas commander and a Gaza-based virtual currency exchange.

Treasury Secretary Janet Yellen said the US “is taking swift and decisive action to target Hamas's financiers and facilitators following its brutal and unconscionable massacre of Israeli civilians, including children.”

“The US Treasury has a long history of effectively disrupting terror finance and we will not hesitate to use our tools against Hamas," she said.

Brian Nelson, US Treasury's under secretary for terrorism and illicit finance, said at a Deloitte anti-money laundering conference Tuesday that the US is renewing its plans to pursue Hamas funding streams and made a call for American allies and the private sector to do the same or “be prepared to suffer the consequences.”

“We cannot, and we will not, tolerate money flowing through the international system for Hamas' terrorist activity,” Nelson said.

“We want to partner with all willing countries and financial entities to stop Hamas financing," he said "but to the extent that any institution or jurisdiction fails to take appropriate action, they should then be prepared to suffer the consequences.”

The shadowy leader of Hamas' military wing, Mohammed Deif, said the Oct. 7 assault on Israel was in response to the 16-year blockade of Gaza, Israeli raids inside West Bank cities over the past year, increasing attacks by settlers on Palestinians and the growth of settlements, among other reasons.

“Enough is enough,” Deif, who does not appear in public, said in the recorded message. He said the attack was only the start of what he called Operation Al-Aqsa Storm, and he called on Palestinians from east Jerusalem to northern Israel to join the fight.