Andrea Sakharov, the dissident Soviet physicist and Nobel Peace Prize winner, was summoned to the Soviet prosecutor's office today and warned that he faces criminal charges unless he ceases his "hostile and slanderous" activities.

Sergel Gusev, deputy chief prosecutor of the Soviet Union, singled out Sakharov's statement on Jan. 14, which suggested that an explosion in a Moscow subway train the weekend before had been an act of provocation by "repressive organs" that intended to use it as an excuse to crack down on Soviet dissidents.

In that statement, Sakharov, said he had been particularly alarmed by a report from Victor Louis, a Soviet Journalist who writes occasionally for the London Evening News, which said flatly that the explosion was caused by a "terrorist bomb." The physicist asserted that the only weapon used by Soviet dissident was public discussion and truthful information.

The prosecutor demanded that Sakharov issue a retraction of his remarks, but the physicist said he refused to do so." I acknowledged that my statement was sharp," Sakharov told reporters at his apartment tonight, "but it was necessitated by the sharp nature of the situation."

The Soviet news agency, Tast, later confirmed Sakharov's account of the warning, saying: "It has been officially told to Sakharov that such slanderous activities are inadmissible in the future and it was explained that if he disregarded the warning he would be brought to account in accordance with the USSR's legislation."

The maximum sentence for "circulation of slanderous fabrications" is seven years with an additional internal exile of five years, but the prosecutor apparently stopped short of saying definitely that Sakharov would be charged.

This was not, moreover, the first time that so strong a warning had been given to the physicist. In August 1973, he was cautioned against passing on information of a "frankly anti-Soviet character." That session was followed by an extended campaign of vilification of Sakharov in the Soviet press that ended without further action being taken.

Since the explosion Jan. 8, three people - a friend of the Sakharov family, a faomer political prisoner now living outside Moscow and Vladimir Albrekht, secretery of the Moscow chapter of Amnesty International have been questioned by police about their whereabouts at the time of the blast. None, however, has apparently been told that he is the target of the investigation and the provailing view among dissidents is still that the whole affair is meant more as harassment than as the beginning of a show trial.

There was no suggestion today that Sakharov might have been responsible for the bombing, in which a number of people were killed and injured, according to unofficial accounts only partly confirmed in the Soviet press. Louis, who has frequently been used by the authorities to publicize sensational information, hinted in his article and conservations with Western reporters that the "terrorist" bomb might have been planted by a dissident group.

Any move against Sakharov, who is the Soviet Union's most prominent dissident, is a serious matter for the Kremlin. More that any other individual, he has come to symbolize the struggle for human rights in Eastern Europe. A concerted effort to silence him would undoubtedly prompt strong condemnation in the West.

Sakharov seemed calm tonight and said he would go on with his activities as before. After the meeting with reporters he and his wife sat down together in their kitchen for tea.