Explosions tore through the departure hall of Brussels airport on Tuesday morning killing one person and injuring several others, the Belgian news agency Belga said.
The agency said shots were fired and there were shouts in Arabic shortly before the explosions.
A still photograph uploaded to social media purported to show black smoke rising from a building at Brussels airport following the blasts.
The blasts occurred four days after the arrest in Brussels of a suspected participant in November militant attacks in Paris that killed 130 people. Belgian police had been on alert for any reprisal action.
Belgian state broadcaster said the Tuesday blasts had left several dead and many injured. National security level was raised to its maximum.
Belgian broadcaster RTBF quoted a hospital source as saying that up to 10 people were killed and 30 more wounded after the explosions.
Another explosion was reported at Brussels Metro Station close to EU institutions, Belgian broadcaster RTBF said.
