GUIYANG, May 13 -- More Chinese cities have stepped up security and tightened armed patrols on the streets after a string of violent attacks sent shockwaves across the country.

Police in Guiyang, capital of southwest China's Guizhou Province, have been equipped with guns and protective devices and have been asked to patrol the city 24 hours a day.

Professional emergency-handling vehicles were also stationed in main areas in the city, and military forces and special policemen were dispatched for joint patrols.

Meanwhile, fully-armed patrol teams were deployed at the city's railway station, bus station and airport.

China has seen a string of violent attacks since March, with two attacks at train stations in Kunming and Urumqi, which left 32 dead and more than 200 injured.

During an inspection in central China's Hunan Province from May 6 to 9, Minister of Public Security Guo Shengkun urged deployment of as many police officers as possible at key public venues during crucial times.

Starting on Monday, Beijing police deployed 150 armed patrol vehicles to city streets to maintain stability in the capital.