A group of left-wing Democrats in the US Congress has withdrawn a letter that called for a negotiated settlement to the war in Ukraine.

The Progressive Caucus said the message was being misconstrued as aligned with a growing reluctance in the Republican party to keep sending aid to Kyiv.

Chairwoman Pramila Jayapal said it was drafted "months ago" and that staff released it without it being "vetted".

The memo sparked intra-party backlash before US midterm elections next month.

The letter to the White House was made public on Monday and was signed in June by 30 of President Joe Biden's fellow Democrats in the House of Representatives.

Its call for the US to negotiate directly with Russia was seen as undermining the Biden administration, which has repeatedly said Moscow is not interested in diplomacy.

White House officials said in response that diplomacy is only possible when all sides are prepared to negotiate, and that is not currently the case.

Massachusetts Democratic congressman Jake Auchincloss denounced the letter as "an olive branch to a war criminal who's losing his war", in reference to Russian President Vladimir Putin.

Another Progressive Caucus member, Ruben Gallego, responded: "Russia doesn't acknowledge diplomacy, only strength.

"If we want Ukraine to continue as a free and democratic country that it is, we must support their fight."

Ms Jayapal, a Washington state congresswoman, said on Tuesday that she still supported an end to the war "with diplomacy".

She said the timing of the letter's release meant it had "been conflated with [Republican] opposition".

Ms Jayapal continued: "It is a distraction at this time."

She accused Republicans of planning to withdraw financial and military support for Ukraine if they win a majority in Congress next month.

Republican congressman Kevin McCarthy warned earlier this month that if his party takes power in November there will be no "blank cheque" for Ukraine.

Other signatories to the letter included New York congresswoman Alexandria Ocasio-Cortez, a leading figure in the party's socialist wing, and Maryland congressman Jamie Raskin, who has taken a lead role in the Democrats' efforts to investigate former President Donald Trump.

Mr Raskin disavowed the letter on Tuesday in a statement condemning Russia as "a world centre of antifeminist, antigay, anti-trans hatred". He praised the Ukrainian armed forces for recruiting women and "sexual minorities".

Ms Ocasio-Cortez has faced pressure over Ukraine at recent public appearances.

One heckler at a town hall-style event accused her of voting for nuclear war with Russia and China, shouting: "Why are you playing with the lives of American citizens?"