Political and military leaders from Cambodia and Vietnam are involved in large-scale illegal logging that threatens to destroy Cambodia's forests, a British environmental group said on Thursday. Cambodian government officials declined comment until they reviewed the report, although Agriculture Minister Tao Seng Huor said Cambodia recently asked neighbours Vietnam, Laos and Thailand to help combat illgal log exports.Members of the environmental group Global Witness said they had seen large stockpiles of illegally exported Cambodian logs in Vietnam worth an estimated $130 million and called on Vietnam to halt timber imports from Cambodia.