Gunmen believed to be al Shabaab militants attacked and injured a security personnel along the Bura-Garissa Road.
The gang also burnt a construction lorry on the same road before escaping in the Wednesday afternoon incident.
Officials said the gang first attacked a vehicle carrying Kenya Defence Forces personnel and injured one.
Other soldiers fought the unknown number of attackers before they retreated into the forest.
Three hours later, the gunmen targeted a construction lorry carrying two Chinese nationals and two police officers in Heyley.
They then burnt down the vehicle before fleeing the scene. The workers and police who managed to escape called for reinforcement and were later rescued.
The injured soldier was taken to hospital.
The incident came as security agencies operating in the area said they were on high alert following reports of terrorists in the area.
The terrorists are targeting projects including the Lapsset port and road.
A Chinese company is constructing the Bura-Garissa road connecting Tana River and Kilifi counties.
The road will lead to Garissa, Isiolo and later to Ethiopia and South Sudan.
The construction comprises of 257 km Lamu-Ijara-Garissa section, which is part of the Lapsset project.
Also, the 113 km Hindi-Bodhei-Basuba-Kiunga section and the 83km Ijara-Sangailu-Hulugho section.
Local police officials said they had deployed more personnel to pursue the gang operating in the expansive Boni Forest.
Northeastern police boss George Seda said no arrest have been made but efforts to trace the gang are ongoing.
The government has blamed ethnic profiling linked to political inclinations around election and land disputes as the primary causes of recent attacks and displacements in Lamu.
There are fears militants are planning an attack on security agencies and civilians.
This has prompted security operations in Mandera, Wajir, Lamu and parts of Kilifi counties.
The area is near the Kenya-Somalia border, which has been prone to terror attacks.
(Edited by Bilha Makokha)
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