Mexico tightens security for Cuba migrants By MARK STEVENSONMEXICO CITY — The Mexican government said Tuesday it was stepping up security at detention centers for illegal Cuban migrants after a group of detainees fought police officers and held a guard against his will - the seventh uprising or mass escape by Cubans in a year.Officials also will deny political asylum to those involved in the latest conflict."After these acts, changes will certainly have to be reviewed to increase the level of security" at immigration holding centers like the one in Mexico City where a dozen Cubans rioted and briefly took over the facilities Monday, presidential spokesman Ruben Aguilar said.The riots are fueled in part by the fact that most Cubans are forced to wait for months inside decrepit Mexican detention centers. The Cuban government often delays recognizing them as a means of punishment for their attempt to leave the island, Mexican officials say.The Cubans involved in Monday`s uprising were demanding they not be returned to the island, saying they feared reprisals there. Eight Cubans were injured in the scuffle, though their injuries were not life-threatening, the government said in a news release...Yet the estimated 500 Cubans detained each year make up a tiny fraction of the approximately 250,000 undocumented foreigners detained in Mexico annually. Most of the detainees are Central Americans, and they are usually released to their home countries in two days or less. But officials say Cuba takes much longer to react.