BERLIN - A prominent British Palestinian doctor said he was “forcibly prevented” from entering Germany on Friday, with the Palestinian solidarity conference he was due slated to speak at shut down by police who detained dozens of activists in the process.

Ghassan Abu Sitta, a reconstructive plastic surgeon who spent 43 days tending to the wounded in Gaza City last year, said that he was questioned for three hours at Berlin’s airport before being told he was not allowed to enter the country. He said he had also been informed he was not allowed to record any videos that could be shown in events in Germany this month.

“Today we saw how accomplices in a crime behave,” Abu Sitta said at a demonstration at the German embassy in London after arriving back in Britain, referring to Berlin’s support of Israel’s war. “Accomplices in a crime try to hide the evidence and silence the witnesses.”

Germany’s interior ministry did not respond to emails requesting comment.

The pro-Palestinian conference at which Abu Sitta was due to speak was broken up by police shortly after he was turned back at immigration. It accuses Germany of being complicit in “Israeli apartheid and genocide” on its website and was scheduled to include speakers such as former Greek finance minister Yanis Varoufakis and Irish politician Richard Boyd Barrett, both known for their Palestinian activism.

Germany has thrown full support behind Israel during its war in Gaza, with the country’s security seen as paramount to the state given Germany’s Holocaust history. It is the second largest arms supplier to Israel after the United States, with Nicaragua lodging a case at the International Court of Justice earlier this week alleging that Germany is aiding genocide through its deliveries. Berlin has called the case “grossly biased.”

Alongside its support for the war has come what officials describe as a “zero tolerance” stance toward antisemitism, which in practice has brought hypersensitivity to pro-Palestinian expression. The slogan “Free Palestine” has been banned in Berlin schools, while a slew of exhibitions and events have been closed over the Palestinian sympathies of artists.

In February, Israeli filmmaker Yuval Abraham caused a firestorm at the Berlin International Film Festival after he called for a cease-fire in Gaza and criticized Israel’s treatment of Palestinians.

Critics have countered that Germany’s intention is to stifle voices critical of Israel’s war, and point to the soft hand of authorities when it comes to antisemitism of White far-right Germans.

“When you see what they are doing to the people in Gaza, this is nothing,” said Abu Sitta, who said that his lawyers would be taking up his removal from the country with the German authorities.

Police shut down the Palestinian solidarity conference about a minute into playing a video message from Palestinian author Salman Abu Sitta - Ghassan Abu Sitta’s uncle. “We have never seen before all means of life systematically destroyed: hospitals, clinics, schools, universities, libraries, ancient monuments, mosques, universities, cemeteries, apartment buildings,” he said before the police intervened.

“Be calm, they are embarrassing themselves,” an organizer told attendees as police cut off the live stream. Around 30 police officers had been in the room of 250 participants to monitor the event, attendees said. They then cut power to the building.

Berlin police said it broke up the event because 86-year-old Salman Abu Sitta is “forbidden from being politically active in Germany.” Seventeen people were detained, according to a police statement which did not give further details on the reasons.

“There is a risk of a speaker being put on screen who in the past made antisemitic and violence-glorifying remarks,” Berlin police said on social media. The last two days of the conference have been banned, it said.

Wieland Hoban - the chairman of Jewish Voice for a Just Peace in the Middle East, which co-organized the event - said the organizers had not been informed in advance that Salman Abu Sitta was under a speaking ban. Two of the group’s members were detained, he said, including one who held up a “Jews against genocide” sign outside the event venue in the morning.

The conference - and Salman Abu Sitta’s participation in particular - stirred controversy before it even began, with Germany’s antisemitism commissioner, Felix Klein, saying he was in favor of banning the author from entering the country. The furor related to a January blog post in which Salman Abu Sitta wrote that he “could have been one of those who broke through the fence” if he were younger and still lived “in the concentration camp called the Gaza Strip.”

Organizers said around 100 police officers showed up at the event Friday morning, but did not raise any concerns with them about the conference program.

In the morning, police had told organizers that building and fire regulations meant that only 250 attendees would be able to attend, with more than double that number planned. Normally routine health and safety checks with police dragged on for several hours, said one organizer who declined to be named for fear of legal repercussions.

Berlin Mayor Kai Wagner praised the police actions. “We have made it clear which rules apply in Berlin,” he tweeted. “We have made it clear that hatred of Israel has no place in Berlin. Anyone who does not abide by these rules will feel the consequences.”