Protesters and police spar in Hong Kong

HONG KONG (CNN) -- Pro-democracy protesters surrounded government headquarters and briefly blocked a key road near the Chief Executive's office in Hong Kong's Admiralty district on Sunday amid calls for an escalated campaign of civil disobedience.

Police used batons and pepper spray to push the protesters back, then demolished steel barricades the protesters had built on Lung Wo Road, a major east-west route.

Protesters retreated, chanting slogans at police who raised a red-flag warning that they might use force to disperse the crowds.

At least two protesters were pushed to the ground and arrested in Sunday's demonstrations, according to Hong Kong media reports.

Police had warned protesters earlier not to block government buildings, saying authorities would take "resolute enforcement action if protesters became unruly."

The tense standoff came at the end of a dramatic week in which Hong Kong authorities moved to dismantle protest camps in the city's Mong Kok district, arresting dozens and drawing accusations of brutality in the process.

Protesters turned their attention to other protest sites, including the main protest site in the Admiralty district, in their continuing quest to force Hong Kong leaders and the Chinese government to allow greater freedom in Hong Kong elections.

The protesters want Hong Kong voters, not a committee influenced by China's central government, to choose candidates in the 2017 election for Chief Executive.

Michael Pearson wrote from Atlanta. Ivan Watson and Vivian Kam reported from Hong Kong. CNN's Anjali Tsui and Felecia Wong also contributed to this report.