In the wake of ’s new policy that bans certain conservative voices from the platform, President Donald Trump tweeted Friday that he will “monitor” social media sites for “censorship of “AMERICAN CITIZENS.”

The President, who has met with social media leaders in the past over such practices as “shadow banning” and platform message removals, issued what amounted to his latest complaint that conservative voices are targeted by the various social media platforms and other tech firms, such as payments systems and search engines. To date, the complaints have not been heeded and have been denied, dismissed or excused as violations of community standards.

Facebook announced on Thursday that it was banning Paul Joseph Watson, Milo Yiannopoulos, Laura Loomer, Alex Jones and Louis Farrakhan. The individuals had their accounts, fan pages and affiliated groups removed on Facebook and its Instagram site. Facebook said they represented “dangerous” views that “promote or engage in violence or hate, regardless of ideology.”

Trump has met with CEO Jack Dorsey, and GOP lawmakers have also complained about their treatment on the sites. Donald Trump Jr. also weighed in on the Facebook removals, saying the “purposeful & calculated silencing of conservatives by @facebook & the ret of the Big Tech monopoly men should terrify everyone. It appears they’re taking their censorship campaign to the next level. Ask yourself, how long before they come to purge you? We must fight back.”