SEOUL, South Korea — Police said Tuesday a 69-year-old man upset over a land dispute has admitted setting the fire in Seoul that destroyed the 14th-century gateway considered South Korea's top cultural treasure.

The suspect in the arson at the Namdaemun gate, identified only by his family name, Chae, was arrested late Monday on Ganghwa Island, west of Seoul.

The suspect "has confessed his crime," said Kim Young-soo, head of a police station handling the case in Seoul.

The fire broke out Sunday night and burned down the wooden structure at the top of the Namdaemun gate, which once formed part of a wall that encircled the South Korean capital. The structure collapsed as hundreds of firefighters attempted to get the blaze under control, officials said. The gate's large stone base remained intact.

Police have a letter from the suspect complaining about a land dispute with a development company. The suspect maintains he did not get enough compensation from the developer for his land in Gyeonggi province near Seoul, Kim said.

Police found a bottle of paint thinner and leather gloves at the house of Chae's ex-wife in Ganghwa Island, said Kim.

Kim said the man had been charged in 2006 with setting fire to the Changgyeong Palace in Seoul, which caused $4,230 in damage.

The two-tiered wooden structure destroyed in this week's fire was renovated in the 1960s, when it was declared South Korea's top national treasure. The government built a plaza around the gate, officially known as Sungnyemun, in 2005 and opened it to the public the following year for the first time in nearly a century.

The gate — with a wooden plaque reading "The Gate of Exalted Ceremonies" in Chinese characters — had been off-limits to the public since Japanese colonial authorities built a nearby electric tramway in 1907. Japan ruled the Korean peninsula in 1910-45.

The Cultural Heritage Administration said it would take at least three years and some $21 million to fully restore the gate.

President-elect Lee Myung-bak visited the scene Monday and deplored the destruction of the landmark, the namesake of Seoul's central district.

Kim Ok-ja, a 40-year-old public servant, said she could not sleep Sunday night after hearing of the fire because her heart was broken.

"I came here immediately after finishing work because my heart aches so much," she said after offering a white flower, a traditional symbol of grieving.