Forensic police officers inspect the scene of a bomb in Omagh, Northern Ireland
A device exploded in Northern Ireland on Saturday, police said, adding that the blast in a shopping area of Londonderry, a city close to the border with Ireland, had caused no injuries.
"There has been an explosion in the Shipquay Street area... The area was evacuated at the time. There are no reports of any injuries," a police statement said.
A police spokesman added in a telephone call with AFP: "We believe it was a sort of device".
The early afternoon blast came one day after Britain's Queen Elizabeth II ended a historic state visit to Ireland and two days before US President Barack Obama arrives in Dublin.