Rajab, president of the Bahrain Center for Human Rights, was taken into custody on Monday after a group of security forces surrounded his house in the village of Bani Jamrah west of the capital, Manama, according to his Twitter account.
The Bahrain Forum for Human Rights confirmed the arrest.
Rahjab has been arrested several times since the start of the anti-regime uprising in the tiny Persian Gulf island in 2011.
He was sentenced to six months in prison in January 2015 for posting tweets critical of the Al Khalifa regime. In May last year, a Bahraini court upheld Rajab's jail sentence.
Rajab, who is also a co-founder of the Gulf Center for Human Rights, has been critical of Manama's heavy-handed crackdown on peaceful anti-regime protests.
The arrest came as the Al Khalifa regime prevented a delegation of activists from traveling to Geneva, Switzerland, to attend the 32nd session of the UN Human Rights Council on Monday.
Since February 14, 2011, thousands of anti-regime protesters have held numerous demonstrations on an almost daily basis in Bahrain, calling for the Al Khalifa family to relinquish power.
In March that year, troops from Saudi Arabia and the United Arab Emirates were deployed to the country to assist the Bahraini regime in its crackdown on peaceful protests.
Scores of people have been killed and hundreds of others injured or arrested in the crackdown.
Amnesty and many other international rights organizations have frequently censured the Bahraini regime for rampant human rights abuses against opposition activists and anti-regime protesters.
Copyright © 2010 Press TV. All rights reserved.