US President Donald Trump on Thursday said he had authorised what he described as a “powerful and deadly strike” against Islamic State militants operating in northwest Nigeria, accusing the group of killing Christians in the region.

In a post on Truth Social, Trump said the operation was carried out “at my direction as Commander in Chief” and targeted ISIS fighters, whom he referred to as “terrorist scum”.

“I have previously warned these terrorists that if they did not stop the slaughtering of Christians, there would be hell to pay — and tonight, there was,” he wrote.

Trump added that the US “Department of War” had carried out “numerous perfect strikes, as only the United States is capable of doing,” and said his administration would not allow “radical Islamic terrorism to prosper”.

He ended the message with a Christmas greeting, adding, “May God bless our military, and Merry Christmas to all, including the dead terrorists — of which there will be many more if their slaughter of Christians continues.”

In recent months, Trump has repeatedly highlighted the plight of Christians in Nigeria. In November, he urged his defence secretary to prepare for possible military action and warned that the US could intervene forcefully to protect Christians in Africa’s most populous nation.