HONG KONG (AP) — Police in the global gambling hub of Macau have arrested five people involved with an informal poll to measure support for direct elections of the Chinese-controlled city's leader.

The five were arrested Sunday after activists kicked off the weeklong unofficial referendum inspired by a similar vote in June in nearby Hong Kong that Beijing denounced as an illegal farce but which drew nearly 800,000 votes.

The arrests are "a serious violation of human rights," said Jason Chao, president of Open Macau Society, one of three groups organizing the poll. "You can feel that how the government fears the result of the referendum."

Chao said he and four others were waiting Monday for authorities to decide whether to prosecute them after being arrested for disobeying government orders not to collect residents' personal data. Macau's government privacy watchdog had warned organizers they were violating the privacy law by collecting identity card data from voters.

Macau was a former Portuguese colony before coming back under China's control in 1999, two years after Beijing regained Hong Kong from Britain. The two cities are specially administered regions of China that have broad say over their own affairs under the principle of "one country, two systems" but whose leaders are chosen by small committees of Beijing-friendly elites.

A 400-person election committee is widely expected to elect the former Portuguese colony's current leader to another five-year term on Aug. 31, the same day that referendum organizers plan to release results of the poll.

Public discontent is rising in Macau, the only place in China where casinos are legal, after a decade-long casino boom that's supercharged the economy but also widened inequality, strained resources and inflated housing prices in the city of about 600,000.