(Adds second witness, details and background)
ABUJA, June 25 (Reuters) - An explosion rocked an area near an upscale shopping centre in the Nigerian capital Abuja on Wednesday, two witnesses said.
It was not immediately clear what caused the blast or if there were any casualties.
The explosion was near the popular Banex Plaza shopping centre in the Wuse 2 district, the witnesses said.
"I heard a loud blast, it shattered the windows of the shop. We ran out. A lot of people ran too, some with blood stains," said Gimbya Jafaru, who was shopping nearby.
Nigeria has been hit by almost daily bomb and gun attacks, which are widely suspected to be the work of Islamist militant group Boko Haram.
The insurgents, who are trying to carve out an Islamist state in the north, have been increasingly moving beyond their traditional base in rural northeast Nigeria.
Abuja has been a target for bomb attacks in recent months. A suspected car bomb in May killed at least 15 and an attack on a bus station a month earlier killed at least 75. (Reporting by Camillus Eboh; Additional reporting and writing by David Dolan; Editing by Janet Lawrence)