Story highlights

NEW: Nabeel Rajab faces charges of "inciting illegal activities and defamation"

He was arrested late Saturday upon arrival in Bahrain

Rajab calls Bahrain's judiciary system "a tool used against human rights defenders"

CNN  — 

A prominent Bahraini human rights activist has been arrested upon his return to the Persian Gulf kingdom from Lebanon, the government and an activist group said Sunday.

Nabeel Rajab, director of the Gulf Center for Human Rights and president of the Bahrain Center for Human Rights, was arrested late Saturday when he arrived at the airport, according to a tweet from Mohammed al-Maskati, a fellow human rights activist.

The Interior Ministry said in a posting on its website that Rajab was “detained under suspicion of committing several punishable crimes,” while the Information Affairs Authority said he is facing charges of “inciting illegal activities and defamation.”

Rajab appeared before a court on charges of “inciting illegal rallies and marches online by using soical media networks,” the Information Affairs Authority said in a statement.

He stood for the arraignment, but did not answer questions about the charges against him, saying he refused to recognize the court, it said. The court ordered him held in custody for seven days, added the statement.

Rajab was charged with “participating in illegal assembly and calling others to join,” and could face further charges of “insulting the statutory bodies” for an incident that occurred April 26, the Bahrain Center’s website said. In its posting, the rights center said that Rajab had decided not to participate in his own trial.

“Given that Bahrain in essence lacks a judiciary system that is independent and/or fair, and is far from being in line with international standards of a fair trial, I have decided to boycott the trial against myself,” the center quoted Rajab as saying before his arrest. “The judiciary system in Bahrain, today, is a tool used against human rights defenders and people calling for democracy and justice.”

Demonstrations in Bahrain failed to gain the traction of other Arab Spring uprisings after a crackdown by authorities in the island state, backed by troops from nearby Saudi Arabia and the United Arab Emirates. Last November, Bahrain’s Independent Commission of Inquiry issued a report critical of authorities’ reactions to the protests, which began in February 2011, spurred by uprisings in Tunisia and Egypt.

The small island kingdom plays a key strategic role in the Middle East, and is home to the U.S. Navy’s Fifth Fleet headquarters.