Senior BJP leader L K Advani today said that the naxalite threat in the country is not of foreign origin, but a home problem, and naxals should trust the democratic system. Addressing a `students' parliament', organised by Maharashtra Institute of Technology in Pune, he said, the naxal elements should be persuaded to shun the path of violence. To a query, he said the issue of illegal immigrants, mainly from Bangladesh, had a bearing on the national security, and government should take steps to deal with it.