Turkish-American political commentator Cenk Uygur said he has been barred from entering the United Kingdom after authorities revoked his travel authorisation ahead of planned events in London and Oxford this week.

Uygur has repeatedly criticised Israel’s military campaign in Gaza and described its actions as genocide.

Political commentator and Twitch streamer Hasan Piker, Uygur’s nephew, said on social media that British authorities had also revoked his visa.

“The UK has revoked my visa as well,” Piker wrote, alleging the decision was made “at the behest of Israel”. Piker is also scheduled to appear at SXSW London this week. South by Southwest (SXSW) is an annual film and music event.