Two protesters climbed onto the roof of the Bahraini Embassy in London on Monday, unfurling a banner in a protest aimed at the Gulf state's ruling family.
An Associated Press photographer saw two men waving a flag on the building's roof. On Twitter, a user identifying himself as Moosa Abd Ali said the activists had occupied what he called the "Al Khalifa den," a reference to Bahrain's ruling family.
A banner draped over the building carried pictures of hunger striking human rights activist Abdulhadi al-Khawaja and senior Shiite opposition leader Hassan Mushaima, both of whom were sentenced to life in prison in Bahrain after last year's pro-democracy protests there.
"Over 60 days on hunger strike," the banner read, in reference to al-Khawaja.
Al-Khawaja, who holds both Danish and Bahraini citizenship, is the focus of an international campaign aimed at securing his release. Daily rallies by his supporters in Bahrain have frequently drawn a violent response from security forces, while Denmark's prime minister has described the activist's condition as "very critical."
Bahrain denies that al-Khawaja's health is failing.
The country is in the grips of a 14-month uprising aimed at weakening the powers of the kingdom's Sunni monarchy, and the Gulf state has recently seen a spike in violence.
The growing unrest, which has included vigilante-style attacks in some Shiite areas, could complicate efforts by Formula One to carry out the April 22 Bahrain Grand Prix.
The race was called off last year amid security fears, and Bahrain's leaders are pushing hard to bring back the event as a sign of stability in the island nation.
London's Metropolitan Police said Monday that it was preparing a statement on the embassy incident. Rescue officials said they had two ambulances standing by at Belgrave Square, which is also home to the embassies of Syria and Germany, among others.
Phone calls to the Bahraini Embassy were not answered.