VATICAN CITY -- During a liturgy underscoring unity with Rome, Pope John Paul II told 28 new archbishops, including two from the United States, to put their trust in God when the church undergoes times of difficulty.

"The church is continually put to the test," he said during a Mass in St. Peter's Square for the feast of Sts. Peter and Paul June 29.

"Whoever trusts in God, liberated from every fear, feels the consoling presence of the Spirit even, and especially, in moments of trial and pain," he said.

The pope gave each archbishop -- named over the previous year -- a pallium, a circular band of white wool marked with six black crosses. The pallium symbolizes the archbishops' authority and unity with the pope.

Among the archbishops from 18 countries were U.S. Archbishops John J. Myers of Newark, N.J., and Alfred C. Hughes of New Orleans.

Reading his homily in a strong voice, the pope said that the message of Sts. Peter and Paul, apostles martyred in Rome, was "clear and eloquent: By the grace of God, man is able in every circumstance to become a sign of the victorious power of God."

"For this reason, he must not fear," the pope said.

The pontiff sat as the archbishops, dressed in brilliant red vestments, came up individually to receive their palliums, which he placed over their heads with the assistance of two aides.

"It was a very moving moment," Archbishop Hughes told Catholic News Service after the ceremony. He said he thanked the pope for his "remarkable ministry" and pledged to carry out his own ministry in communion with Rome.

"He thanked me," the archbishop said.

Of all the new archbishops, the pope lingered longest -- nearly half a minute -- with Archbishop Tadeusz Kondrusiewicz of Mother of God in Moscow, a church territory upgraded to an archdiocese in February. The pope smiled and animatedly gestured several times during their brief conversation.

The Vatican's decision to create the Moscow archdiocese and three other Russian dioceses chilled relations with the Russian Orthodox Church and drew criticism from other Orthodox churches, concerned about alleged Catholic expansion in traditionally Orthodox countries.

Nonetheless, as in years past, the Mass was attended by a three-man delegation from the Ecumenical Orthodox Patriarchate of Constantinople, this year headed by Metropolitan Panteleimon of Belgium. In his homily, the pope said their traditional presence was a "providential moment" on the way to full communion.

Also attending the liturgy was a Bulgarian Orthodox delegation headed by Metropolitan Simeon of Central and Western Europe. Addressing them at the end of the Mass, the pope recalled his visit to Bulgaria in May and invoked "celestial blessings on the faithful of that dear nation."

Both delegations approached the pope for a fraternal embrace, and Metropolitan Simeon, with a smile on his face, planted a kiss on the frail pope's right temple.

The 82-year-old pontiff presided over the Mass' Liturgy of the Word, but sat to the side while Cardinal Angelo Sodano, Vatican secretary of state, celebrated the rest of the Mass. Gathered around Cardinal Sodano at the altar were the new archbishops, many of whose faces glistened with perspiration in the late-afternoon, Roman summer heat.

The group of archbishops who received the pallium included two Canadians: Archbishop Emilius Goulet of Saint-Boniface, Manitoba, and Archbishop Anthony G. Meagher of Kingston, Ontario. Archbishop Andre Richard of Moncton, New Brunswick, could not be present for the ceremony.