Prominent Bahraini activist Maryam al-Khawaja was arrested after arriving in the island nation over the weekend.
"To be clear, I'm officially under arrest on unknown charges," al-Khawaja tweeted Saturday. "They will bring me before a judge tomorrow at an unknown time."
She has said that she wants to visit her father, Abdulhadi al-Khawaja. He has been on hunger strike since August 24, according to the Bahrain Center for Human Rights.
Bahraini authorities released a statement Monday citing a "case that was presented to them from the Bahrain airport police." Without mentioning Maryam al-Khawaja by name, the statement said the "accused person" had an outstanding warrant and was arrested upon arriving in Bahrain, according to Abdullah al-Dossary, district attorney for al-Muharraq province.
"At that point, while she was being searched, she was asked by the police to surrender her telephone, which she refused and assaulted a police officer and a female police officer and caused injuries as accompanied by the medical reports," the statement said.
In the presence of her attorney, the woman was charged with assaulting a state employee while performing official duties, based on witness statements and the medical reports of the officers who were allegedly attacked, al-Dossary said. She was then sent to jail for seven days while the investigation is conducted, the statement said.
Abdulhadi al-Khawaja's other daughter was also briefly detained after attempting to visit her father Thursday, the Bahrain Center for Human Rights said.
Abdulhadi al-Khawaja was sentenced to life in prison in 2011 on charges related to participating in anti-government demonstrations and plotting to overthrow the Gulf nation's royal family.
Maryam al-Khawaja's Twitter account, which was taken over by "someone close to the al-Khawaja family," said that she will face three sets of charges: one related to a human rights campaign, one related to insulting the king and one related to assaulting police.
The investigation has been extended for seven days, and al-Khawaja is not allowed to see a lawyer before her interrogation, according to her Twitter.
The 27-year-old -- who holds Bahraini and Danish citizenship -- is one of the most visible figures speaking out against Bahrain's government.
Bahrain, a majority Shiite nation, is ruled by a Sunni monarchy. The country experienced its own set of protests that started during the Arab Spring and have continued for the past three years.
Demonstrators say authorities killed dozens of people and imprisoned hundreds of others while cracking down on dissidents.
"The thing about Bahrain is that nobody really knows what's going on there because there's not much media coverage," al-Khawaja said last year.
Bahrain is a U.S. ally that hosts the Navy's 5th fleet.