A huge explosion has rocked the centre of the Hungarian capital Budapest sparking fears of a terror attack.
Police sources said they believed the attack was deliberate and may have been targeting police officers.
Witnesses described seeing an attacker waiting in a doorway before throwing the explosive device packed with nails at two officers as they passed by the buidling.
The incident comes just a week before Hungarians go to the polls in a nationwide referendum that will set the direction of the country’s migration policy.
The explosion shattered glass windows and caused panic in the surrounding streets, with scores of emergency vehicles rushing towards loud blast, which witnesses initially believed to be triggered by a gas leak.
The police officers found nails in the area and are now investigating reports it may have been thrown at officers by an assailant who fled the scene shortly after the blast.
Officials confirmed that two police officers were injured and were taken to hospital.
Wtinesses described seeing a young female officer with head injuries from a “splinter” while a male officer suffered injuries to his feet.
She is said to be fighting for her life in a critical condition while the male officer is expected to make a full recovery.
The scene has since been declared safe by security officials, following a huge police presence at Teresa Boulevard in the Oktogon area.
Sources said a lot of nails were covering the ground around the area of the explosion.
Expert onsite inspections are still ongoing in a bid to discover the exact cause of the incident.
Hungarian police released a statement on it’s official website asking anyone who was in the area at the time of the detonation to contact them immediately.
Police refused to comment further but said they would be holding a news conference later on Sunday.
The Hungarian PM has been a vocal opponent of immigration into Europe and is urging voters to reject EU quotas for resettling migrants in Hungary in a referendum next Sunday, arguing immigration increases security risks.
Hungary has seen only a trickle of migrants since it sealed its southern border with Serbia with a razor wire fence last year.