COLOMBO — Sri Lanka's navy arrested a boatload of people heading to Australia and raised the number of would-be illegal immigrants detained this month to a record 500, an official said Sunday. A fishing trawler carrying 31 people was intercepted off the island's western coast on Saturday, and another 20 were arrested on shore ready to board the vessel, the navy official said. “We had the highest number of arrests this month,” said the official, who asked not to be named. “We stopped eight trawlers off the eastern coast and three off the western coast as they set off for Australia.” The official said the figures were in contrast to 200 people arrested between May and June, and that the July arrests were the highest on record during a one-month period. Most of the would-be illegal immigrants had paid up to Rs300,000 ($2,300) as an advance for the perilous journey and were to give an additional Rs400,000 ($3,000) on reaching Australian shores, according to the official. The boatpeople have been handed over to the Criminal Investigations Department for investigations, the official said, adding that most of them wanted to claim political asylum in Australia. — AP