Hong Kong Chief Executive Carrie Lam's government again pushed back on a key demand of protesters as a downtown rally turned violent, showing the unrest that began last June still has no end in sight.

In a lengthy statement Sunday, a government spokesman recapped failed attempts to implement a promise of universal suffrage since China took control of the former British colony in 1997. It said that Hong Kong's residents need a "clear understanding" that any chief executive elected by all citizens shall also be accountable to Beijing.

"This is the constitutional order under the 'one country, two systems' principle which should not be ignored," the spokesman said. "The community needs to attain a consensus on these principles, and premised on the legal basis, to narrow differences through dialogues under a peaceful atmosphere with mutual trust."