U.S. President Joe Biden has criticized Benjamin Netanyahu's war strategy in Gaza as "hurting Israel more than helping."

The comment came in an interview aired Saturday as the U.S. leader's impatience with his Israeli counterpart grows increasingly visible.

With Gaza's humanitarian crisis growing more dire and Biden's left flank in uproar, the U.S. president made contradictory remarks as to the question of a "red line" over Israel's threatened offensive on Rafah in southern Gaza.

Netanyahu "has a right to defend Israel, a right to continue to pursue Hamas," Biden said, but added that "he must pay more attention to the innocent lives being lost as a consequence of the actions taken."

"In my view, he is hurting Israel more than helping Israel," he said.

As to Israel's potential invasion of Rafah, where some 1.5 million of the territory's 2.4 million residents are now crammed, Biden was ambiguous.

"It is a red line," the 81-year-old Democrat said, immediately adding: "I am never going to leave Israel. The defense of Israel is still critical.

"There is no red line (in which) I want to cut off all weapons so they don't have the Iron Dome (air defense system) to protect them."

He then once again countered that there were in fact "red lines ... You cannot have 30,000 more Palestinians dead."

After Biden's State of the Union address Thursday, he was caught on a hot mic stating that he'd told Netanyahu they would need to have a "come to Jesus" meeting, an American expression that refers to a dramatic realization that one must correct course.

Despite Biden's shift in tone, his administration has given short shrift to activist calls to cut the billions of dollars in military aid the United States sends to Israel.

Gaza has faced relentless bombardment by Israel since the Oct. 7 Hamas incursion that resulted in about 1,160 deaths, according to official figures.

Israel's retaliatory war on the Palestinian enclave has killed more than 31,000 people, mostly women and children, according to the territory's Health Ministry.

Biden was evasive Saturday on the possibility of a new trip to Israel, which he visited in October shortly after the Hamas incursion, and which included a speech to lawmakers.

Asked if it was something he would do again, Biden responded "yes" but declined to say whether he was invited.