A Russian court on Monday sentenced U.S. national, Paul Whelan, to 16 years in prison for espionage, state media reported.

Whelan, a former U.S. marine, was accused of having obtained classified Russian state information, the nature of which has not been disclosed.

U.S. Ambassador John Sullivan described it as a secret trial in which no evidence was produced.

Sullivan, present at the courthouse in Moscow, condemned the proceedings as an egregious violation of human rights and international legal norms.

Whelan, 50, has been in Russian custody for the past one year and a half after being detained in Moscow in December 2018.

He underwent surgery two weeks ago for an abdominal hernia.

The U.S. embassy said it was an emergency surgery performed because the condition had become a life-threatening one.

A flash drive and documents were confiscated from Whelan while he was detained on a trip to Moscow.

No further details about the evidence have been revealed, while Whelan insisted that he was innocent.

His family said he was in Russia to attend a wedding and not what the Russian Government claimed.

Meanwhile, Whelan’s legal team vowed to appeal the verdict.

Whelan, born in Canada to British parents, is also a citizen of Canada, Britain and Ireland.

He was employed by the U.S. auto parts supplier BorgWarner upon his detention.

(dpa/NAN)