A prominent human rights activist in Bahrain has been arrested on accusations of posting derogatory tweets about a group of his countrymen allegedly cooperating with Islamic State (Isis).

Nabeel Rajab was detained after being summoned to the criminal investigation department in the capital, Manama, on Wednesday in connection with a series of tweets he posted late last month.

His wife, Sumaya, told the Guardian that officials had ordered Rajab to remain in detention for seven days for further investigations.

The Bahraini interior ministry said Rajab had been summoned because of what it said were derogatory tweets aimed at defaming the government.

“The general directorate of anti-corruption and economic and electronic security summoned Nabeel Ahmed Abdulrasool Rajab on Wednesday to question him about the tweets posted on his Twitter account that denigrated government institutions,” it said in a statement.

The ministry said Rajab had acknowledged the charges against him and his case had been referred to the public prosecutor.

Sumaya Rajab said her husband’s lawyer had been able to meet him on Thursday and was present at some of the interrogations, which are believed to have focused on tweets he posted in English and Arabic in late September about a group of Bahraini men working with Isis.

“Many #Bahrain men who joined #terrorism & #ISIS came from security institutions and those institutions were the first ideological incubator,” he tweeted last month.

many #Bahrain men who joined #terrorism & #ISIS came from security institutions and those institutions were the first ideological incubator — Nabeel Rajab (@NABEELRAJAB) September 28, 2014

Rajab’s friends said the tweet was posted in reaction to a video released by Isis that featured a group of Bahraini men talking about their cooperation with the terrorist organisation.

Hours before his arrest, Rajab tweeted that he had received a phone call from the criminal investigation department and was waiting for a written summons before going there.

I received a call from the Criminal Investigation dep to go immediately to Cyber Crimes Dep. waiting for written summon in order to go. — Nabeel Rajab (@NABEELRAJAB) October 1, 2014

His wife said: “He will be kept for another seven days in al-Hurra police station in Manama for investigation. They’ll decide after that whether to keep him longer, refer him to the court or release him.”

She said her husband’s detention was also linked to his recent trip to a number of western countries, which was aimed at raising awareness about rights abuses in his country.

Rajab, who has served time in prison in Bahrain in the past due to his human rights activities, spoke to the Guardian last month about the upcoming parliamentary elections in November.

Reacting to the Guardian article, Salman al-Jalahma, a media representative with the Bahraini information affairs authority, wrote on a government website: “It is unfortunate that the author [of the Guardian article] chose to only reach out to an opposition member for his personal account of the country’s progress.

“Although Mr Rajab may have a bleak outlook on the country’s future, this is not representative of the Bahraini populace, nor of the opposition front.”

Sayed al-Wadaei, of the Bahrain institute for rights and democracy, who accompanied Rajab on his recent visit to London, criticised the UK government for its reaction to human rights abuses in Bahrain.

“Since being released from two years of arbitrary imprisonment in May 2014, Nabeel Rajab has travelled around Europe advocating for human rights. He has been subsequently detained in only two places, Bahrain and the United Kingdom,” he said, referring to his brief detention and questioning at Heathrow airport.

“The arrest of Nabeel once more in Bahrain for a tweet indicates that Bahrain is nowhere close to the reform that it has been claiming to undergo. His detention at Heathrow in the UK signified the unwavering support of the UK government for Bahrain’s regime, despite its severe human rights abuses, paving the way for the continuation of impunity in the kingdom.”

In London, Rajab participated in a protest calling for the release of his fellow rights activists jailed in Bahrain, including Maryam al-Khawaja, the prominent dissident who was arrested in Manama in August after returning to see her father, who is on hunger strike in prison.