Thousands of Hong Kong pro-democracy activists forced the temporary closure of government headquarters on Monday after clashing with police, defying orders to retreat after more than two months of sustained protests in the Chinese-controlled city.

Hong Kong leader Leung Chun-ying said police had been tolerant but would now take "resolute action," suggesting that patience may have finally run out.

Chaos erupted as commuters made their way to work, with hundreds of student-led protesters surrounding Admiralty Centre, which houses offices and retail outlets, in a standoff with police. The central government offices and the legislature were forced to close in the morning, as were scores of shops.