WASHINGTON (Reuters) - The United States has suggested Uzbekistan grant "humanitarian parole" for a former opposition politician who has spent 22 years in prison and whose sentence was recently extended by another three years, a senior U.S. diplomat said on Tuesday.


Samandar Kukanov, 72, a former parliamentary deputy, was sentenced to 20 years in prison in 1994 on embezzlement charges, and in 2014 his term was prolonged for two more years for a breach of prison rules, according to local rights group Ezgulik.


His relatives and the rights group on Monday said a court in Uzbekistan had handed down an additional three-year sentence to a man described by human rights activists as one of the longest-serving political prisoners in the Central Asian nation.


Asked if the United States had called for Kukanov's release, Assistant Secretary of State for South and Central Asian Affairs Nisha Biswal told Reuters: "We have."


"We have raised with them the idea of humanitarian parole as a way of providing an opportunity for these individuals who have spent an extraordinary amount of time in prison, who are toward the end of their life, to be able to be home with their families," she said in an interview.


Kukanov's relatives were expecting his release in October but instead received a letter from prison authorities saying he had again been found guilty of violating prison regulations, according to the letter, which his relatives posted online.

The letter did not say which regulations he violated.

Rights groups and opposition members say Kukanov, once a chief executive of an oil refinery, became "a personal enemy" of Islam Karimov, Uzbekistan's late president, after criticizing him and supporting opposition movements.

Karimov died in September from a stroke after ruling the Central Asian nation of 32 million people with an iron fist for almost 27 years.

Prime Minister Shavkat Mirziyoyev, who has become interim president and is widely expected to win a Dec. 4 presidential election, has amnestied several less-prominent political prisoners. But country-watchers expect no significant changes in Uzbekistan's restrictive political environment.

(Reporting By Arshad Mohammed and David Brunnstrom in Washington and by Olzhas Auyezov in Almaty; Editing by Alan Crosby)