The United Kingdom has blocked entry to left-wing US commentators Cenk Uygur and Hasan Piker, preventing them from attending scheduled speaking events in London and Oxford.

Axar.az reports, citing Reuters, Uygur, co-host of the YouTube channel The Young Turks, and Piker, a prominent political streamer, said they were denied entry due to their views on Israel.

The UK Home Office said travel authorisation for the pair had been revoked because their presence “may not be conducive to the public good,” without referencing Israel.

Both were due to speak at the SXSW London festival this week, with Piker scheduled for a panel on online political communication and Uygur set to discuss technology and economic power structures.

Organizers have not publicly commented on the decision.

“I’ve been banned from the UK. I tried to get on a flight to London to attend SXSW London and give a speech at Oxford. I’ve been banned for criticizing Israel. Are we free anymore?” Uygur reacted on social media.

Piker similarly said his visa was revoked and suggested the decision followed political pressure.