Islamist militants may already be operating in Northern Ireland, the local leader of the UK Independence Party (UKIP), David McNarry, has said.
He cited newspaper claims that Irish police were more concerned about "ISIL" (or so-called Islamic State) cells in Dublin than dissident republicans.
He said he hoped the Police Service of Northern Ireland (PSNI) would be given more money to tackle the threat.
The MLA for Strangford was speaking at UKIP's regional party conference.
Mr McNarry asked: "Are we here in Northern Ireland, who treat dissident activity extremely seriously, missing a trick by not knowing if there is a threat to our communities, as is apparent down south from ISIL supporters?
"Because, be in no doubt - all the connotations of migration will take pole position in this [European Union] referendum debate - a debate we welcome but which no-one will welcome with the ISIS gun held to our heads.
"And listen up - we cannot live with other people's terrorists in our midst," he said.
"Nor should we be either asked or expected to provide work for other people's unemployed, when local workers are losing their jobs or provide homes when young couples languish on housing waiting lists for years.
"Nor should we rush to send money by pledging £200m to Africa when we must get our own needy sorted first."
Asked later by the BBC to clarify his remarks about the threat from ISIL in Northern Ireland, Mr McNarry said: "If they are in Dublin why wouldn't they be here?
"That's what I'm saying. It's a hundred miles down the road, why wouldn't they operate here?
"We are worried about them in every other city in the United Kingdom. The chancellor of the exchequer has just given millions more money to the police.
"Im hoping our [PSNI] chief constable is going to get a lot more money too, to chase down and run down ISIL terrorists, if they are here."