Police and firefighters have raised their vigilance levels in the capital ahead of the impending annual conventions of the country's top legislature and top political advisory body.

Measures to safeguard the sessions include a ban on unscheduled flying objects near the city and scheduled non-stop police patrols and intensified checks on traffic hubs such as subway stations.

The two annual sessions of the National Peoples' Congress and Chinese People's Political Consultative Conference will begin on March 3 and end in mid-March.

According to Xinhua News Agency, the first 25 police pavilions have been erected at traffic hubs, in busy commercial districts and other places in the city center to allow the police to coordinate their 24-hour street patrols.

Meanwhile, a local newspaper reported on Monday that Beijing police had imposed a ban on any flying activities for sports, entertainment or promotional purposes within a 200-km semi-diameter of Tian'anmen Square from March 2 to March 15.

A rough measure on a map shows the ban affects not only aviation activities in the capital but also in a large part of neighboring Hebei province and Tianjin.

The local police authority said it had worked with government agencies in civil aviation, meteorology, education and commerce to implement the ban.

Beijing citizens are also advised to report any suspicious flying object to police immediately.

On Tuesday, a China Daily reporter saw an increased police presence around the Great Hall of the People -- the main venue for both sessions -- which is opposite Tian'anmen Square.