British police said yesterday they were treating a blast outside a mosque in central England as a terrorist incident, saying nails were reportedly found at the scene.
West Midlands police said they were alerted to reports of a loud bang in Tipton near Birmingham shortly after 1pm. No injuries were reported, but the immediate area was evacuated.
"An investigation is being led by the West Midlands Counter-Terrorism Unit and it is being treated as a terrorist incident," police said.
"Some residents have reported finding debris in the area and finding nails. This is being investigated by forensic officers at the scene."
Two suspects, both British Muslims, face a murder trial in November.
Since Rigby's killing, the English Defence League (EDL), a right-wing group which vociferously opposes Islamism, has staged protests at which its supporters chanted slogans such as "Muslim killers off our streets". A mosque was burned down in London shortly after the killing and "EDL" scrawled on the side of the building, but it was unclear who caused the fire.
Police have said there has been a rise in the number of attacks on Muslims since Rigby's death, despite politicians and religious leaders appealing for calm.
At Rigby's funeral, flowers spelling out the words "daddy" and "brother" decorated the flag-draped coffin, which was carried by scarlet-uniformed drummers from Rigby's Fusiliers regiment at Bury Parish Church in northern England.
Rigby's two-year-old son Jack wore a blue T-shirt with the words: "My Daddy My Hero" and "My Daddy's a Fusilier". He entered the church in the arms of his mother, Rebecca.
Hundreds of veterans in uniform cheered his sobbing family and thousands more well-wishers followed the service via loudspeakers outside the church.
"People were shocked at what happened on the streets of Britain," said Dennis McCormick, a 65-year-old veteran from the parachute regiment.
Prime Minister David Cameron and London Mayor Boris Johnson attended the funeral.