A prominent human rights activist Nabeel Rajab has been arrested, his family members said on social media. Rajab led numerous protests during the Arab Spring and repeatedly criticized the Bahraini government on Twitter.

“Rajab has just been arrested and his house was searched,” his wife Sumaya Rajab wrote on Twitter.

The authorities also seized all the activist’s electronic devices, without explanation, his family said, as cited by the Middle East Eye.

HRD Nabeel Rajab has just been arrested from his house and his house was searched #bahrain@NABEELRAJAB — Sumaya Rajab (@binmrajab) June 13, 2016

Sumaya Rajab later told RT that security officials, who arrived to detain her husband were “wearing civilian clothes.”

“Around 5:00am, 30 people came to our house and said that they had a warrant to search our house and arrest Nabeel. They spent around half an hour searching the house and took Nabeel’s electronic devices,” she said.

The reasons for Rajab’s arrest, the man who founded the Bahrain Centre for Human Rights, remain unclear.

His wife said when she asked the security officials about it: “They replied that they didn’t know. They’d just been ordered to do so.”

Former member of the Bahraini parliament Jalal Fairooz told RT that Rajab contacted his family on the phone later on Monday, saying, “he has been taken to one of the worst interrogation places in the city of Riffa.”

Rajab kept asking the authorities about the official allegations against him, but was denied an answer, he said.

“Also he wasn’t allowed a lawyer,” Fairooz added.

The former MP said it was no coincidence that Rajab’s arrest took place on the day of the beginning of the UN Human Rights Council session in Geneva, as the activist was to address the event via Skype.

“Probably, because Nabeel spoke to RT and other TV stations, the authorities didn’t like that. They just don’t want anyone to say ‘no.’ Just yesterday there was a delegation of human rights activists, who were stopped at the airport, preventing them from going to Geneva,” he added.

Nabeel Rajab house was searched and he was arrested #Bahrain#NabeelRajab#humanrights — Nabeel Rajab (@NABEELRAJAB) June 13, 2016

Rajab, a prominent human rights activist and president of the Bahrain Center for Human Rights (BCHR), has repeatedly advocated freedom of expression and debate.

READ MORE: ‘I will continue tweeting, I will continue criticizing’ - Bahrain activist Nabeel Rajab

Rajab has organized numerous protests against the Bahraini regime since 2011 and has been in and out of jail on numerous occasions. He was arrested in 2012 and spent two years in prison for his tweet criticizing the government and three protest-related charges. He was re-arrested in 2014 for several months for criticizing the authorities on Twitter.

الدخول للمنزل واعتقال والدي نبيل رجب ، Police entered the house and arrested my father Nabeel rajab #Bahrain — Adam Rajab (@AdamNabeel) June 13, 2016

He was sentenced in 2015 to six months in prison for a tweet considered insulting to the Gulf Kingdom’s Ministries of Interior and Defense. His tweet suggested that Bahraini security institutions could act as an "ideological incubator" for terrorism and Islamic State militants.

Later in 2015, the activist was pardoned by King Hamad bin Isa al-Khalifa. However, Rajab said he still faced a sentence of up to 10 years for insulting the government institution.

Speaking on his pardon to RT, he said that he will continue tweeting and criticizing Bahraini authorities. “I’m going to continue my human rights struggle, and my struggle for democracy, and human rights in this part of the world,” he said.

Arresting human rights activist Nabeel Rajab After the police stormed into his house without a warrant.#Bahrainpic.twitter.com/OHrlRmuujN — BAHRAIN DETAINEES (@BH14Detainees) June 13, 2016

READ MORE: ‘I could be arrested any moment’ – Bahraini opposition activist Nabeel Rajab to RT

Bahrain, an island kingdom, has been repeatedly criticized for suppressing basic freedoms. According to such groups as Amnesty International and Human Rights Watch (HRW), the kingdom continues to imprison activists arbitrarily and subject them to torture.

Anti-government protests have been taking place in Bahrain since the start of the Arab Spring uprising across the region. The kingdom, which hosts the US Fifth Fleet, brutally cracked down on a popular uprising in 2011. The majority Shia population of Bahrain complains of discrimination and lack of democracy in the oil-rich kingdom, while the Sunni monarchy often accuses its archrival Iran – a Shia powerhouse – of instigating unrest in the country.