Four people were injured in an attack by gunmen on a Chinese road construction site in Shimbirey, about 50 km from Garissa town on Sunday evening, Kenyan police confirmed on Monday.

Garissa County Police Commander David Kerina, who visited the scene, said swift response by the police helped save lives.

The police are pursuing militants suspected to have crossed from neighboring Somalia after escaping on foot toward Dadaab area, Kerina said.

"As per the tracking, quite a number of them sustained bullet injuries and we are right on their heels. Sooner we shall catch up with them," Kerina told journalists in Garissa town.

He said the security officers guarding the camp returned fire and in about 15 minutes were able to repulse the militants who fled to nearby thicket.

The police said the attack occurred at around 8 p.m. on Sunday.

According to locals who did not want to be named, eight hooded militants, all armed with AK-47 rifles, kidnapped a man from a nearby village and ordered him to take them to the camp of the construction site.

As they approached the camp, they started shooting arbitrarily, prompting the workers who are housed outside the fenced camp to scatter for safety.

During the shootout, the wife of one of the security guards manning the gate was shot from behind and a bullet is said to be lodged in her shoulder.

She was rushed to hospital and her condition is now stable. Three others were also injured, including the husband of the injured woman.