Gen. Czeslaw Kiszczak, a Polish general and communist-era leader who played a key role in imposing martial law in 1981, has died. He was 90.

After Gen. Wojciech Jaruzelski, the nation's top leader at the time, Kiszczak was the most important figure in the crackdown aimed at crushing the pro-democracy Solidarity movement. Martial law included the mass round-up and interment of Solidarity activists, curfews and other harsh measures.

Both men long argued that they acted to stave off a Soviet invasion.

Kiszczak was also the last prime minister of communist Poland, a job he only held briefly in 1989 before the country's transition to a free-market democracy.

He died on Thursday in Warsaw, according to his family. Jaruzelski died in 2014.