Tusk accused of treason related to plane crash in 2010

European Council President Donald Tusk has been questioned by Polish prosecutors, appearing as a witness in what has been described as "a highly sensitive political investigation."

Military prosecutors are investigating allegations of secret illegal contacts between Polish and Russian Intelligence Officials during the period when Tusk was Poland's Prime Minister, from 2007 to 2014.

Tusk spent more than eight hours in closed door questioning on wednesday.