The ministry confirmed that Al-Khawaja has been detained in Bahrain along with her 16-month-old son but said it wasn't immediately known if her detention marked the beginning of a three-year prison sentence she was given for “insulting” Bahrain's king, Hamad bin Isa Al Khalifa, by ripping up his picture.
“We received notification in the afternoon from some of the relatives. We have asked the embassy in Saudi Arabia to investigate further. The embassy will ask for access, as is standard practice when Danes are imprisoned abroad,” Ole Egberg Mikkelsen, the head of the Foreign Ministry's Citizen Services, told news agency Ritzau.
Danish Foreign Minister Kristian Jensen criticised the Bahraini authorities for arresting someone simply for expressing their opinion.
“We oppose all forms of imprisonment in connection with human rights violations, and we have expressed that numerous times to Bahrain's foreign minister,” Jensen told Ritzau.
Zainab al-Khawaja's father, Abdulhadi Al-Khawaja, has been held in a Bahraini prison since 2011, serving a life sentence for demonstrating against the government and organising protests during the Arab Spring uprisings.
In the spring of 2012, Abdulhadi al-Khawaja held a 110-day hunger strike that sparked what Denmark's then Foreign Minister, Villy Søvndal, called the “largest Danish consular effort ever” to obtain his release.
He staged another short-lived hunger strike in September 2014, that was called off over health concerns for other prisoners who had joined him in his protests.
Zainab's sister, Maryam al-Khawaja, was held by the Bahraini authorities for 19 days in the autumn of 2014 on charges that she attacked a police officer in a Bahraini airport after arriving from Denmark to visit her father in prison. She was sentenced in absentia and faces imprisonment if she returns to Bahrain.
Amnesty International accused the Bahraini authorities of a witch hunt against the al-Khawajas.
“Zainab Al-Khawaja and her family have been relentlessly targeted by Bahraini authorities for speaking out against human rights violations,” James Lynch, the agency's deputy director in the Middle East and North Africa, said in a statement.
“Her convictions are for nothing more than tearing up photos and seeking to visit her father in prison. If this arrest means the start of her prison sentence, she will be a prisoner of conscience, jailed solely for peacefully exercising her right to freedom of expression," he added.
Abdulhadi al-Khawaja lived in the Copenhagen area for 12 years, during which time he obtained Danish citizenship, before moving back to Bahrain in 2001 to lead resistance movements against the local government. Both of his daughters are dual citizens of Bahrain and Denmark.