VATICAN CITY (Reuters) - Israel's Embassy to the Holy See issued a protest on Monday after a Yemeni Nobel Prize winner accused Israel of "genocide" in Gaza during an event hosted by the Vatican.

The embassy said it felt "indignation and shock" over the comments from rights activist Tawakkol Karman made on Saturday evening during a conference organised by the Fratelli Tutti Foundation created by Pope Francis.

Karman, who won the 2011 Nobel Peace Prize for her role in the Arab Spring protests, told an audience in the atrium of St. Peter's Basilica: "The world is silent in front of the genocide and the ethnic cleansing of the Palestinian people in Gaza."

   In an open letter posted on X on Monday, the Israeli embassy rejected Karman's accusations as "lies".

"The site was contaminated by a flagrantly anti-Semitic speech," it said.

"We regret that such a speech was pronounced without anyone feeling the moral duty to intervene to stop this disgrace," it added.

After mentioning Gaza, Karman got a loud round of applause from the audience which was made up of fellow Nobel prize laureates, politicians and church officials. The pope himself was not present.

Relations between the Vatican and Israel have grown increasingly tense since the start of the war in Gaza, with Jewish groups accusing Pope Francis of failing to describe the invasion of the Palestinian enclave as an act of self-defence after the Oct. 7 Hamas attacks.

In March, the Israeli embassy to the Holy See criticised Cardinal Secretary of State Pietro Parolin after he accused Israel's military of causing "carnage" in Gaza.

The embassy initially denounced his comment as "deplorable" but subsequently said this was a translation error and that it had meant to say "regrettable".

(Reporting by Crispian Balmer; Editing by Andrew Heavens)