A group calling itself the IRA claimed responsibility for sending devices to army recruitment centres by contacting a Northern Irish media outlet on Saturday, police have said.
A Metropolitan Police statement read:
We are aware of the claim of responsibility for the devices that were sent to army recruitment centres in England last week.
The claim was received on Saturday, 15 February by a Northern Irish media outlet using a recognised codeword.
The claim was allegedly made on behalf of the 'IRA'.
The public is urged to remain vigilant and report anything suspicious to the Anti-Terrorist Hotline 0800 789 321.