President Donald Trump warned Thursday that the United States could carry out additional military strikes in Nigeria if attacks on Christians there continue, remarks that underscore growing U.S. attention to violence in West Africa and revive debate over the religious dimensions of the conflict.

In an interview published by The New York Times, Mr. Trump framed the December U.S. military action in Nigeria—conducted on Christmas Day against Islamic State-affiliated militants in the country’s northwest—as potentially the first of multiple strikes. The president said the United States had carried out the operation at the request of Nigeria’s government and signaled readiness to act again if Christians continued to be targeted.

“I’d love to make it a one-time strike ... But if they continue to kill Christians, it will be a many-time strike,” Mr. Trump told the newspaper.

The U.S. military has said the December strike targeted Daesh operatives responsible for violent activity in the region. Nigerian authorities described the action as a “joint operation” against “terrorists” and stressed it was not directed at adherents of any particular religion.

The president’s comments came after questions about casualty patterns in the conflict. When The New York Times asked about a prior assertion by one of his Africa advisers that both Boko Haram and IS-affiliated groups were killing more Muslims than Christians in Nigeria, Mr. Trump acknowledged that Muslims were being killed as well but reiterated his view that “it’s mostly Christians.”

Nigeria has long wrestled with a complex security landscape in which Islamist insurgents such as Boko Haram and Islamic State West Africa Province (ISWAP) operate alongside communal and criminal violence, particularly in the country’s northeast and in central farming regions. The Nigerian government has consistently rejected claims that Christians are being singled out for systematic persecution, and officials have emphasized the multifaceted nature of the threats.

Washington’s strike and Mr. Trump’s subsequent comments highlight the diplomatic sensitivities surrounding foreign military action and the challenge of distinguishing sectarian targeting from broader insurgent and communal violence. The administration’s posture signals heightened U.S. willingness to engage militarily in support of partners confronting extremist groups in Africa, while raising questions about how religious identity is being assessed and invoked in U.S. policy decisions.

U.S.-Nigeria cooperation on counterterrorism has expanded in recent years, though such operations remain politically sensitive in both capitals. The president’s remarks are likely to prompt further scrutiny from Nigerian officials, regional partners and human-rights observers concerned with civilian protection and the accuracy of claims about who is being targeted in the country’s ongoing violence.