Tennis players have been warned about security ahead of the start of the Mexican Open in the Pacific resort of Acapulco.
The professional men's tennis association, the ATP, cautioned against travelling outside hotels. Players have been advised to leave the city immediately after being eliminated from the tournament.
Among the players attending the six-day tournament, which opened on Monday, are the defending men's champion, David Ferrer of Spain, who said he had no fears about being there.
But David Nalbandian of Argentina said on Saturday he was thinking about withdrawing, adding that he also had a groin injury. "It's a great and enjoyable tournament to play," he said. "But for right now it's a little more difficult because of the security situation. We [players] are a bit scared about this and we're trying to decide what to do."
More than 34,000 people have been killed in drug-related violence in Mexico since late 2006.