Update:Brussels under attack.!Second explosion reported at metro station

Explosions tore through the departure hall of Brussels airport on Tuesday morning killing 10 persons and injuring over 30 several others, the Belgian news agency Belga said.

The agency said shots were fired and there were shouts in Arabic shortly before the explosions.

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.

Social media showed pictures of smoke rising from the departure hall where windows had been shattered by the blasts. Passengers were seen running away down a slipway.

Sky News television's Alex Rossi, at the scene, said he heard two "very, very loud explosions".

"I could feel the building move. There was also dust and smoke as well... I went towards where the explosion came from and there were people coming out looking very dazed and shocked."

The Belgian broadcaster RTBF quoted a witness as saying there were people injured or unconscious in the departure area, opposite the Sheraton hotel.

Niels Caignau, a Swissport employee, told Flemish broadcaster VRT: "I was on a break and heard and felt a big explosion - we have from here a view over the departure hall and saw a plume of smoke come out.

"The windows are completely shattered. People went outside in shock. It doesn't look good."

(BBC)