US President Donald Trump has ordered the preparation of plans for military action in Nigeria to tackle Islamist militant groups, accusing the government of not doing enough to halt the killing of Christians.

Trump did not say which killings he was referring to, but claims of a genocide against Nigeria’s Christians have been circulating in recent weeks and months in some right-wing US circles.

Groups monitoring violence say there is no evidence to suggest that Christians are being killed more than Muslims in Nigeria, which is roughly evenly divided between followers of the two religions.

The government of Africa’s most populous nation has not responded to the threat of US military action.

However, Nigeria’s President Bola Tinubu insisted that there was religious tolerance in the country and said the security challenges were affecting people “across faiths and regions”.

Trump wrote in a social media post on Saturday that he had instructed the US Department of War to prepare for “possible action”, a

He warned that he might send the military into Nigeria “guns-a-blazing” unless the Nigerian government intervened, and said that all aid to the country would be cut.

Trump added: “If we attack, it will be fast, vicious, and sweet, just like the terrorist thugs attack our CHERISHED Christians!”

Trump earlier announced that he had declared Nigeria a “Country of Particular Concern” because of the “existential threat” posed to its Christian population. He said “thousands” had been killed, without providing any evidence.

This is a designation used by the US State Department that provides for sanctions against countries “engaged in severe violations of religious freedom”.

Following this announcement, Tinubu said his government was committed to working with the US and the international community to protect communities of all faiths.

“The characterisation of Nigeria as religiously intolerant does not reflect our national reality,” the Nigerian leader said in a statement.

Jihadist groups such as Boko Haram and Islamic State West Africa Province have wrought havoc in north-eastern Nigeria for more than a decade, killing thousands of people – however most of these have been Muslims, according to Acled, a group which analyses political violence around the world.

In central Nigeria, there are also frequent clashes between mostly Muslim herders and farming groups, who are often Christian, over access to water and pasture.

Deadly cycles of tit-for-tat attacks have also seen thousands killed, but atrocities have been committed on both sides and human rights group say there is no evidence that Christians have been disproportionately targeted.

Additional reporting by Chris Ewokor in Abuja