The attack took place at the Public Works Department (PWD) office in Cantonment area, and left engineer V.K. Singh and two contractors critically injured.
"The three received multiple bullet injuries and are being treated at a hospital, where their condition is stated to be critical," police inspector V.K. Mishra told reporters in Varanasi, some 300 km from Lucknow.
According to police, the two gunmen, who had their faces covered, managed to escape by scaring the people by firing in the air.
"As of now, we cannot establish the exact reason behind the incident. Investigations are on," he added.
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