Residents have told of the dramatic scenes after police swooped on a van in a late-night security operation in rural Tyrone.
Officers detained two men during the incident outside Fintona around 2am yesterday.
Some nearby homes were evacuated as a huge operation continued until yesterday afternoon involving Army bomb experts.
Police later said a substantial quantity of material, believed to be fertiliser, had been removed and taken away for examination.
The men, aged 33 and 45, remain in custody at Antrim police station.
The alert was centred on Corbally Road, between Fintona and Tempo.
Witnesses described being woken around 2.30am and seeing surrounding fields lit up by flares.
They also reported large numbers of heavily armed police officers in the area.
Police said the search and security operation involved officers from F district and the crime operations department.
It is understood officers were acting on intelligence.
Some sources speculated that officers may have moved too early.
Yesterday the van remained on the road with its rear doors open while Army bomb experts used two robots to examine inside.
DUP Assembly Member Tom Buchanan said the security operation had greatly alarmed the community. He praised the police for their response.
“The community around Fintona is greatly shocked by this news,” he said.
“It’s a quiet area and no one would expect anything like this.”
Mr Buchanan said it was reassuring that police were remaining vigilant in the area.
“I was speaking with the police early this morning and I’ve communicated my gratitude and that of the community for their hard
work,” he added. “The people of Fintona and the surrounding countryside want to live peaceably with their neighbours.
“I trust the community will work with the police to ensure that anyone trying to drag this community back through terrorism is removed from the streets.”
Ulster Unionist MLA Ross Hussey, who sits on the Policing Board, also praised the PSNI. “This incident is a further reminder of the dangers which the police and Army must face every day in order to protect the public,” he said.
“The vast majority of people in Northern Ireland long for the day when security alerts and bomb disposal teams are a thing of the past.
“The community must play its part and give the police every possible assistance in tracking down those who still seek to pursue violence and bringing them before the courts.”
A PSNI spokesman said: “A substantial quantity of material, believed to be fertiliser, has been removed from a Transit van which was stopped by police shortly before 2am this morning.
“The material has been taken away for detailed examination.
“Two men, aged 33 and 45, arrested earlier remain in custody at the serious crime suite at Antrim police station.
“Police apologise for any inconvenience and thank the community for their patience and support.
“We understand the disruption these operations can cause to the community but emphasise that the operation was necessary to keep people safe.”