Peter Robinson, first minister of Northern Ireland, sometimes attends James McConnell’s mega-church on the shores of Belfast Lough. Photograph: Brian Lawless/PA
Amnesty International has accused Northern Ireland’s first minister, Peter Robinson, of letting down the victims of racist attacks in the region by siding with a born-again Christian pastor who has deemed all Islam evil and “the spawn of the devil”.

The first minister defended Pastor James McConnell over the preacher’s anti-Islam tirade a fortnight ago at a church Robinson occasionally attends.

On Wednesday the Democratic Unionist leader said he would not trust any Muslims that were “fully devoted to sharia law”, adding: “I wouldn’t trust them for spiritual guidance.”

Robinson had entered the row over McConnell’s remarks by stating that the preacher did not have “an ounce of hatred in his bones”.

While Amnesty International said it was up to the police to decide if the pastor had “crossed the line from free speech to hate speech” the organisation made clear it believed that the first minister’s remarks were unacceptable.

Patrick Corrigan, the human rights organisation’s programme director in Northern Ireland, said: “What is clear is that amid a rising tide of racist attacks and other hate crimes in Northern Ireland, religious and ethnic minorities deserve much better leadership than they appear to be getting right now from the first minister.”

A fortnight ago McConnell told his congregation at the Whitewell Metropolitan Tabernacle: “Islam is heathen. Islam is satanic. Islam is a doctrine spawned in hell.”

But Robinson, who sometimes attends McConnell’s mega-church on the shores of Belfast Lough, was quoted in the Irish News on Wednesday as describing the pastor as “someone who preaches the gospel”.

The Democratic Unionist party leader said he would continue to visit McConnell’s church.

The preacher’s comments are subject to a police investigation following complaints. McConnell has defended his remarks, which he said were prompted by the story of a pregnant woman, Meriam Yahya Ibrahim, who was sentenced to death in Sudan after refusing to recant her Christian beliefs.

McConnell said he would not bow to what he described as “the powers of darkness”. The pastor is no stranger to controversy and the wide range of targets for his denunciations have included even the Protestant Orange Order in the past.

This is the second time this month that the first minister has become embroiled in rows over rising racism and xenophobia in Northern Ireland.

Before the local and European elections, the deputy first minister, Martin McGuinness, accused Robinson of cowardice for allegedly failing to stand up to loyalist terror group the Ulster Volunteer Force in his East Belfast constituency over a sharp rise in racist attacks. The police have blamed the UVF for orchestrating several recent acts of racist intimidation in the east of the city.

This latest controversy over McConnell’s outburst has further poisoned the already toxic relationship between the first and deputy first ministers. McGuinness said Robinson needed to show leadership and oppose intolerance. But Robinson subsequently tweeted on Wednesday that he would not “take lectures from a self-confessed leader of a bloody terrorist organisation”.