Nov 24 (Reuters) - YouTube said on Tuesday it had barred the right-wing outlet One America News Network from posting new videos for a week after it broke the site's rules against content that claims there is a guaranteed cure for COVID-19.

A spokeswoman for YouTube, the video-sharing platform owned by Alphabet's Inc's Google, said OAN had also been suspended from monetizing its videos due to repeated violations of the COVID-19 misinformation policy and other rules. OAN will have to reapply to be allowed to monetize again.

President Donald Trump has promoted OAN, calling it a "great alternative" to Fox News in a tweet this month. The outlet has amplified Trump's unsupported claims of voter fraud in the U.S. presidential election.

YouTube said it has a "three-strikes policy" before an account is removed and this constituted OAN's first strike. OAN did not immediately respond to a Reuters request for comment.

The YouTube spokeswoman said an OAN video, now removed, had violated its coronavirus misinformation rules by claiming that hydroxychloroquine, an anti-malarial drug touted by Trump despite a lack of scientific evidence, was a cure for COVID-19.

YouTube and other major online platforms are under scrutiny from lawmakers and researchers to curb misinformation on their sites. Following the November election, Reuters identified several YouTube channels making money from ads and memberships that were amplifying debunked accusations about voting fraud.

At a congressional hearing last week with the CEOs of Facebook Inc and Twitter Inc, Democratic Senator Richard Blumenthal criticized Google, YouTube's owner, saying it had been given a "pass" and was being rewarded for its "timidity" in content moderation.

Four Democratic senators also sent a letter on Tuesday to YouTube's Chief Executive Officer Susan Wojcicki urging the video platform to remove content that they said spread misinformation on election results and pressing for information on measures taken ahead of the runoff U.S. Senate elections in Georgia. (Reporting by Elizabeth Culliford; Editing by Tom Brown)