South Korea's defence ministry is considering deploying robots armed with guns along its border with North Korea.
The heavily fortified border has been in place since the 1950s
The robots are designed to strengthen surveillance, ministry spokesman Shin Hyun-don told reporters.
The 4km (2.5 mile) wide Demilitarised Zone (DMZ) separating North and South Korea is already the most heavily fortified border in the world.
Hundreds of thousands of troops patrol the frontier, which has been closed since the Korean War ended in 1953.
The defence ministry said on Friday that it would complete a feasibility study of the planned system by the end of 2005, and the robots could be in operation as early as 2011.
"If the surveillance system by robots is effective, we may withdraw part of our troops away from the border," a ministry official told the Associated Press news agency.
240 km long and 4km wide, the DMZ takes up about 0.5% of Korean peninsula
N Korea has 1.1 million man army along the border. S Korea and US forces total more than 700,000
According to officials quoted in the Korea Times newspaper, the cost of the project could run to $1.9bn.
South Korea has been anxious to improve security on the border with the North since three holes were discovered in the frontier fence in October.
At first Seoul feared that North Korean agents had infiltrated the South, but officials eventually concluded that the holes had been made by a South Korean civilian defecting to the North.
This is not the first time South Korea has deployed robots to help its defensive capabilities.
Two rifle-equipped robots were reportedly deployed with South Korean troops in Iraq.