One of the largest Facebook groups connecting Ukrainian refugees with British host families has warned of the dangers of infiltration posed by Russian trolls and traffickers.

Room for Ukrainians in the UK is a Facebook group created a little over two weeks ago and which already has 12,500 members. Most of those posting are Ukrainians who need sponsors and Britons who want to open their homes to newcomers.

However, the group’s founder, Diana Shore, 57, an assistant professor at a British university, said that in addition to generous offers of help, she also had to tackle Russian trolls trying to infiltrate the group. She also raised concerns that traffickers are taking advantage of the lack of government regulation and oversight of the Homes for Ukraine program.

Shore called on Facebook to step up and use the same type of software used by online dating agencies that identifies the geographic location of someone posting, so that trolls in Russia or elsewhere who try to damage and disturb the site can be more easily spotted and blocked.

His appeal comes as a Russian court banned Facebook and Instagram from doing business in Russia on the grounds that its parent company, Meta, is an “extremist organization”.

Right now, Shore has to resort to searching the profiles of people who posted suspicious things for any mention of “Russia.” Not all trolls will necessarily be Russian or use the word Russia in their Facebook profiles, so it’s not always possible to identify trolls among the group’s 12,500 members.

While Shore praised the success of the group’s members – at least 50 Ukrainian families have been matched with UK sponsors – she urged Facebook and the government to do more to ensure the site is safe. She also urged those using the group to register with the government program and posted backup notices in Russian and Ukrainian on the site.

Shore said the group’s offensive posts include those urging Ukrainian men who have applied for accommodation to return to their country, regardless of their age, health status and other circumstances, and abusive comments that qualify the Ukrainian wives of “whores”.

Shore said she started the group because she felt she had to do something to help.

“It’s a tragedy comparable to World War II,” she said. “I didn’t think it was OK to stay away. My grandfather helped liberate the Belsen concentration camp. He was driving one of the first trucks that entered it at the end of the war. My goal was to find 50 homes for the refugees and we did.

“Only the government has the capacity to provide a safe matchmaking service,” she added. “At the moment that is left to charities and social media. Modern slavery and trafficking are disasters waiting to happen. The matching process needs to be regulated urgently under the oversight of an independent Ofsted-like regulator.

“Facebook’s Mark Zuckerberg needs to step up. I want to protect this site. I need to be able to more easily identify people with malicious intent so I can block them. Social media has also been a force for good with the war in Ukraine. Humanity connects arms across politics, across borders and across languages.

Facebook and the Ministry of Upgrading, Housing and Communities were approached.