Several cities have enhanced security after a terrorist explosion killed three people including two assailants in a railway station in Urumqi, capital of the Xinjiang Uygur autonomous region, on Wednesday.

The blast, which happened on the day President Xi Jinping concluded his visit to the region, left 79 people injured, including four in serious condition.

Medical teams were sent to Urumqi by the National Health and Family Planning Commission to help the injured.

After the attack, security authorities in major cities, including Beijing, Shanghai and Guangdong's provincial capital Guangzhou, and such provinces as Jiangsu and Liaoning, said more armed police are being deployed for regular patrols on the streets, and at scenic spots and rail and bus stations.

Beijing police are on high alert, with officers patrolling the streets around the clock during the May Day holidays from Thursday to Saturday.

The municipal government said more police will be deployed, especially in public areas, such as railway stations and high-traffic areas.

Police started an antiterrorist exercise at the Beijing Railway Station at 11:55 pm on Thursday.

Officers arrived at the drill scene 50 seconds after a warning was issued. All of the forces had arrived and had established a temporary command headquarters within 15 minutes.

The exercise ended early on Friday morning.

Security authorities have been dealing with a recent increase in terrorist attacks. On March 1, knife-wielding terrorists killed 29 people and injured 143 at a railway station in Kunming, capital of Yunnan province.

Amid rising public security concerns, Shanghai's public security bureau has deployed more than 1,000 police officers equipped with revolvers to patrol the streets since late April.

Security authorities in Jiangsu province have deployed 4,000 armed police officers and 12,000 assisting personnel for regular patrols from Thursday to Saturday.

On the streets of Guangzhou, more than 10,000 police officers and assisting personnel have been on patrol since Thursday. The city has installed 397,000 surveillance cameras.

wangqian@chinadaily.com.cn