The Santiago bureau chief of United Press International was expelled from Chile tonight by government authorities who said they were seeking to ensure that foreign correspondents "conform to the truth" about national events.

Anthony Boadle, 31, was arrested by police at the UPI office in Santiago this evening, escorted to the airport and placed on a flight to Lima, Peru, UPI workers said. A government communique charged that he had falsely reported the deaths of two civilians and a soldier during protests in Santiago Tuesday night.

In Washington, a UPI spokesman said that "no such story moved on the UPI wires" and that a protest would be lodged in Santiago.

The expulsion followed the government's suspension of credentials for all foreign correspondents working in Chile and marked the strongest action taken against international journalists since the first years of the 11-year-old military rule.

Acting under a state of siege, the government of Gen. Augusto Pinochet shut down six opposition publications earlier this month and applied strict censorship to the rest of the Chilean media. Since then, several high-ranking officials have complained about international reporting and said measures were being considered to control foreign correspondents.

Col. Carlos Krumm, a presidential palace spokesman, said earlier this week that the government was preparing a law regulating foreign journalists. Other officials have said that reporters considered objectionable by the government may not be issued credentials.

Foreign journalists received letters here Tuesday informing them that their credentials had been suspended and adding that they should apply "promptly" to renew them. Since then, several reporters working here have been issued new credentials.

The government communique issued tonight said that Boadle's expulsion "in no way affects" UPI as an agency. A staff member said Boadle, a British citizen, had been working in Chile about 18 months.