Israel is resuming the water supply to southern Gaza, Energy Minister Israel Katz said Sunday, as one million people have evacuated the north of the Strip to escape a massive air assault.

"This will push the civilian population to the southern (part of the) Strip," Katz said in a statement, a week after Israel had stopped supplying water to the entire territory as part of a "complete siege" on the Palestinian enclave.

He said the decision to resume the supply was taken after talks between Prime Minister Benjamin Netanyahu and US President Joe Biden.

US National Security Advisor Jake Sullivan earlier said that Israel told him it has turned the water supply back on in southern Gaza.

"I have been in touch with my Israeli counterparts just within the last hour who reported to me that they have, in fact, turned the water pipe back on in southern Gaza," Sullivan told CNN. 

But AFP correspondents in southern Gaza said the water had still not resumed.

Israel had halted the flow of water as part of its siege of the Hamas-ruled territory since the war broke out last weekend.

Israel embarked on a withering air campaign against Hamas militants in Gaza after they carried out a brutal attack on Israel on October 7 that left more than 1,400 people killed in Israel.

The widespread air assault has also killed at least 2,450 people in the Palestinian territory.

An estimated one million people have been displaced in the first seven days of the conflict in Gaza, the United Nations agency supporting Palestinian refugees said Sunday.

"The number is likely to be higher as people continue to leave their homes," UNRWA Director of Communications Juliette Touma told AFP.