WASHINGTON, Oct 20 (Reuters) - President Joe Biden on Thursday asked Americans to spend billions more dollars to help Israel fight Hamas while Israel's defence chief told his troops to be ready to go into the Gaza Strip to destroy the Palestinian militant group.

In a televised White House speech late on Thursday that also addressed Ukraine's effort to repel Russia's invasion, Biden said Hamas sought to "annihilate" Israel's democracy.

The president, who made an eight-hour visit to Israel on Wednesday, also stressed the urgency of getting relief to Palestinian civilians in Gaza who lack food, water and medicine.

"We can't ignore the humanity of innocent Palestinians who only want to live in peace and have opportunity," he said.

Biden said he would ask Congress on Friday to approve extra funding for Israel. A source familiar with the matter earlier said it would total $14 billion.

The money would "sharpen Israel's qualitative edge" and strengthen its military capabilities, Biden said.

He said America's national security required it to support "critical partners" like Israel. “It’s a smart investment that’s gonna pay dividends for American security for generations,” Biden said.

On the ground in the Gaza Strip, Israel appeared to be getting closer to a full-scale invasion of the seaside enclave ruled by Hamas. The Israeli military massed troops and equipment near the Gaza border.

"You see Gaza now from a distance, you will soon see it from inside. The command will come," Israeli Defence Minister Yoav Gallant told troops gathered at the Gaza border on Thursday.

Israel has pounded Gaza with air strikes over the Oct. 7 rampage by Hamas gunmen who killed 1,400 Israelis. Israel has put the Gaza Strip's 2.3 million people under siege and has signalled a fullscale invasion.

"All the indications are that the worst is coming," Jordanian Foreign Minister Ayman Safadi told reporters in Amman.

Civilians in Gaza say their situation is increasingly desperate as they run short of food, water, fuel and medical supplies. Some 3,500 people have been killed and more than a million have been made homeless, according to Palestinian health officials.

Photo from AFP