DUBAI, United Arab Emirates (AP) — Bahrain detained three activists over protests targeting the tiny island nation's king during a royal horse show in the United Kingdom, a fellow campaigner said Saturday.

Sayed Ahmed Alwadaei, the director of advocacy at the Bahrain Institute for Rights and Democracy, said those detained include his sister, Sayed Ahmed.

Family members of Alwadaei have been targeted by authorities in Bahrain since he jumped on a car carrying King Hamad bin Isa Al Khalifa during an earlier trip to London.

Alwadaei said his family and those of other activists continue to be targeted to limit public dissent against the country's rulers amid a major crackdown on dissent in Bahrain in years after its rulers crushed its 2011 Arab Spring protests.

Bahraini authorities did not immediately respond to a request for comment Saturday as government offices were closed for the weekend.

The detentions come as activists have been protesting King Hamad's presence at the Royal Windsor Horse Show taking place in Britain. Already, state-run Bahrain News Agency photographs have shown King Hamad there with Queen Elizabeth II and Dubai's ruler, Sheikh Mohammed bin Rashid Al Maktoum.

Alwadaei said he believed the detentions were aimed at disrupting protests targeting King Hamad's visit to Britain.

"This is a new low by the Bahraini authorities to blackmail activists by detaining their families in Bahrain," he said.

Bahrain is home to the U.S. Navy's 5th Fleet and an under-construction British naval base.

Since the beginning of a government crackdown last year, activists have been imprisoned or forced into exile. The kingdom also began trying civilians in military tribunals.

Independent news gathering on the island also has grown more difficult, with the government refusing to accredit two Associated Press journalists and others.