ROME (AP) _ The respected Roman Catholic periodical 30 Giorni (30 Days) said Monday it would cease publication indefinitely to protest criticism of a group close to the monthly magazine by the Vatican's official newspaper.

Another magazine said it would join the protest by issuing its next edition blank.

The Vatican's L'Osservatore Romano on Monday criticized a recent convention held by the conservative Italian Catholic group Communione e Liberazione (Communion and Liberation).

The newspaper said the convention barely dealt with religious subjects or new ideas, and instead focused on particular political issues. It attacked the group for criticizing the decision of the Italian president, Francesco Cossiga, to dissolve Rome's government.

Cossiga made the decision after Mayor Pietro Giubilo resigned in the wake of allegations of a conflict of interest in the awarding of contracts for school lunches. Giubilo, who denied blame in the scandal, was a supporter of Communione e Liberazione.

Marco Bucarelli, president of the board of directors of 30 Giorni, said the magazine was ceasing publication indefinitely as a protest.

''Such a grave decision is motivated by the attempt mounted by ideological- po litical factions to limit the freedom of expression and action of Catholic lay people,'' he said.

The magazine's staff also issued a statement in support of the publisher's decision.

''For some time, and without any restraint, the directors of the Vatican daily have taken advantage of the moral authority of the Holy See for ideological-political maneuvers that, apart from breaking with the glorious tradition of the paper, put serious limitations on the freedom of opinion of the faithful,'' the statement said.

30 Giorni said the halt of publication applied to its Italian, French, American, Spanish and Brazilian editions.

Il Sabato, a weekly magazine that also is close to Communione e Liberazione, said its edition due out Thursday would be blank to protest the Osservatore Romano article.