Brussels attack: New York brother and sister missing after 'phone line went dead'

'Their mother is worried sick since she can't get hold of them'

A family are desperately searching for a brother and sister from New York who were phoning home during the Brussels attacks when "the line went dead".

Sascha and Alexander Pinczowski rang their mother from Zavantem Airport to say they had arrived safely - but have not been heard from since the phone line cut out during the explosions on Tuesday.

The pair's mother and friends have posted messages across social media requesting that emergency and hospital workers get in touch if they have information, according to the New York Post.

"Their mother is worried sick since she can't get hold of them since this morning when they were checking in at Zaventem airport," wrote friend Mafalda De Andrade Vasconcelos on Facebook.

Alexander Pinczowski is being searched for by his girlfriend and mother (Facebook/Karen Van Suijdam)

The siblings, who are residents in New York and were visiting their father in the Netherlands, were reportedly checking in at the American Airlines desk in the airport.

Reports have said the airport bombs went off near both the American Airlines and Brussels Airlines check-ins.

Ms Pinczowski graduated from Marymount Manhattan College, reportedly speaks five languages and was recently working as a production intern at the Chelsea production and design company Shiraz Events, according to the New York Post.

"She was very determined and fun. She was a pleasure to have around," said Florecia Sadler, a producer at the company.

Ms Pinczowski's brother's girlfriend was also asking for people to help find the two siblings.

The first bomb went off in Zaventem airport at about 8am local time, or 7am British time with another following a few minutes later. Together the bombs are believed to have killed at least 11 people.

One hour later a third bomb was detonated at Maalbeek Metro station, leaving about 20 people dead and dozens wounded.

Two of the bombers have been named as Khalid and Brahim el-Bakraoui and a third fugitive being searched for by police has been named as Najim Laachraoui.