Authorities in Bangladesh have arrested a leading human rights activist on charges of "fabricating information" about atrocities committed by state security forces in a government crackdown this year.

Plainclothes police officers arrested Adilur Rahman Khan, secretary of Bangladeshi human rights organisation Odhikar, at his home on Saturday night as he returned with his family.

Bangladesh has been hit by protests and demonstrations ahead of elections due later this year. Prime Minister Sheikh Hasina's government has come under fire from the opposition for, among other things, a controversial trial of war criminals and numerous cases of alleged corruption against its ministers. At least 150 protesters have reportedly been killed in clashes with police since February, according to Human Rights Watch.

Khan's organisation has been critical of human rights abuses allegedly committed by Bangladeshi security forces, including torture, extra judicial killings and enforced disappearances.

His organisation reported that between January and June 2013, 184 people were illegally killed by Bangladeshi law enforcement agencies.

His lawyers applied for bail for the rights chief today but the petition was rejected.

"Adilur Rahman Khan is a lawyer of the supreme court of Bangladesh, he is a former deputy attorney general and he is a human rights defender. It is an insult and shame that a magistrate can actually pass an order of remand on a fellow officer of the court," said Saira Rahman Khan, the activist's wife and founding member of Odhikar. She continued,: "Neither Odhikar nor he works for any political party but for human rights and the people of Bangladesh."

Human Rights Watch condemned Khan's arrest. "Adil is one of the leading human rights activists in Bangladesh and someone we have worked with closely on sensitive issues such as extrajudicial killings, torture and labour rights," Brad Adams, the organisation's Asia directortold the Guardian.

Adams continued: "He has been a strong critic of each of the past governments and has been threatened and followed for a long time. We are concerned for his safety. It appears he is being persecuted for his criticism of the current government."

British high commissioner in Bangladesh Robert Gibson was "concerned at the arrest of Odhikar secretary Adilur Rahman", he said in a tweeter post on Sunday.

Several rights groups including HRW and the Asian Human Rights Commission (AHRC) have issued appeals to the Bangladeshi government to release Khan.reported the AHRC.

Khan and his colleagues have been previously intimidated and followed closely by security forces for publicly criticising police brutality. In 2007, Odhikar's director, ASM Nasiruddin Elan, was picked up by security forces in Bangladesh and taken to the country's navy intelligence headquarters. Odhikar stated (pdf) that "he was physically assaulted and threatened with death" before he was released.