Turkey's Recep Tayyip Erdogan on Monday said US President Joe Biden had "bloody hands" because of his support for Israel in the raging conflict in the Gaza Strip.

The Turkish president's comments represented one of his strongest attacks on Biden since his arrival in the White House in January.

Erdogan had spent the past few months trying to mend relations with Washington and reaching out to other Western allies after a year of sharp disputes.

But he lashed out at Biden directly in a furious nationally televised address.

"You are writing history with your bloody hands," Erdogan said in remarks addressed to the US president.

"You forced us to say this. Because we can not stay silent on this anymore."

Erdogan has gained support across the Middle East by vocally championing the Palestinian cause during his 18-year rule.

He had accused Israel last week of waging "terrorism" and vowed to rally the world to Gaza's defence.

"Today we saw Biden's signature on weapons sales to Israel," Erdogan said on Monday in reference to US media reports of a new arms shipment approved by the Biden administration.

"Palestinian territories are awash with persecution, suffering and blood, like many other territories that lost the peace with the end of the Ottomans. And you are supporting that," Erdogan told Biden.