A Bahraini court sentenced rights campaigner Nabeel Rajab to two years in jail on Monday, supporters said, for allegedly making "false or malicious" statements about authorities.

The Bahrain Institute for Rights and Democracy (BIRD) said Rajab had been unable to attend the trial, having been at an Interior Ministry hospital since his health deteriorated in April. He was detained a year ago.

"This outrageous sentence against someone speaking the truth exhibits the brutality of the Bahraini government and its heinous crimes and that of its kangaroo court," said Sayed Al-Wadaei, director of advocacy at BIRD.

Authorities at Bahrain's information affairs office could not immediately be reached for comment. Bahrain has repeatedly denied systematic rights abuses.

In a January 2015 media interview cited by the prosecution, according to al-Wadaei, Rajab had said Bahrain's jails housed political prisoners who were subject to torture.

Rajab was a leading figure in a 2011 pro-democracy uprising that was crushed by the government with the help of fellow Gulf Arab countries.

He was arrested in June last year after posts from his Twitter account suggested security forces had tortured detainees in a Bahraini prison and during a military campaign in Yemen.

U.S. DISAPPOINTED

The U.S. State Department said it was "disappointed" by the sentencing and called for Rajab's release.

"We continue to strongly urge the government of Bahrain to abide by its international obligations and commitments to respect human rights and fundamental freedoms, including the freedom of expression," the department said in a statement.

Amnesty International called Rajab's imprisonment "a flagrant violation of human rights and an alarming sign that the Bahraini authorities will go to any length to silence criticism."

Human Rights First said the ruling was "blatant injustice designed to serve political interests."

Rajab criticised U.S. President Donald Trump in a New York Times column in May for selling arms to his country and Saudi Arabia, citing their human rights records.

Trump's White House has approved a $5 billion military sale to Bahrain, home to the U.S. Navy's Fifth Fleet, that was held up by the previous administration of Barrack Obama last year because of human rights concerns.

Rajab faces further charges related to an earlier New York Times article and tweets from his account critical of the intervention in the Yemen war by a Saudi-led coalition.

The Sunni-ruled kingdom, most of whose population is Shi'ite, says it faces a threat from neighbouring Shi'ite theocracy Iran.

It accuses Iran of radicalising and arming some members of its majority Shi'ite population in an effort to bring about the downfall of the ruling Al Khalifa family. Tehran denies any meddling in Bahrain.