Threat to commuter line

Federal and Los Angeles officials said yesterday a ‘‘specific’’ threat had been called in from a foreign country against the city’s Red Line commuter rail system, prompting them to alert the public. ‘‘This threat is imminent ... it is very specific,’’ Los Angeles Police Chief Charlie Beck told an evening news conference. ‘‘But the credibility still needs to be vetted.’’ Law enforcement officials at the news conference said the threat had been relayed to the Federal Bureau of Investigation by a law enforcement agency in another country, where the threat had originated. Officials did not identify the country.