The ecumenical patriarch of Constantinople, the spiritual leader of 250 million Orthodox Christians, continues his historic trip to the United States today with a visit to the National Council of Churches in New York.

Dimitrios I arrived in New York yesterday for the second leg of his month-long U.S. tour. His visit marks the first time an ecumenical patriarch has visted America.

The patriarch is considered first among equals by several Orthodox churches, including the Albanian, Bulgarian, Carpatho-Russian, Greek, Polish, Russian and Ukrainian Orthodox churches.

Tonight he will attend a dinner given by New York Gov. Mario M. Cuomo and tomorrow a lunch given by New York City Mayor David N. Dinkins. Tuesday he is scheduled to meet with United Nations General Secretary Javier Perez de Cuellar.

On Monday the patriarch will conduct a thanksgiving service and blessing at Ellis Island and the Staute of Liberty to commemorate Orthodox Christians who immigrated to America.

New York is the home of the nation's largest population of Orthodox Christians, with about 1 million people. Astoria, Queens, boasts the nation's largest Greek Orthodox community, and there, the patriarch will lead a service Tuesday night.

The 75-year-old leader lives in Istanbul. The Turkish government had been restricting his travel, but in recent years he had visited England, Eastern Europe and the Soviet Union.

He began his U.S. visit last week in Washington, where he laid a wreath at the Tomb of the Unknowns, attended a performance at the Kennedy Center, met with President Bush and congresssional leaders and opened the 30th Biennial Greek Orthodox Clergy-Laity Congress.

The 3,000 people who attended the congress discussed a variety of issues facing the church and made small revisions -- the first since 1978 -- in the Charter of the Greek Orthodox Archdiocese of North and South America, said James Peponis, a co-convenor of the Congress.

One of the most unusual visits of Dimitrios I's Washington stay was his trip to Saint Nicholas Cathedral, which is part of the Orthodox Church in America, a distinct branch of the Orthodox Church that has been involved in a 20-year dispute with other Orthodox churches over its status.

At the cathedral, Dimitrios I exchanged greetings with Theodosius, the archbishop of Washington and all America and Canada in the Orthodox Church in America. The two church leaders have been estranged because of the conflict over whether the Orthodox Church in America should have been established as a separate entity with that title.

When the patriarch leaves New York on Wednesday, he will make a one-day visit to Allentown and Johnstown, Pa., cities with large Ukrainian Orthodox populations. One topic of discussion there will be the future of the church's enormous Eastern European membership now that Soviet bloc countries are placing fewer restrictions on religious practice.

From Pennsylvania, the religious leader will travel to San Francisco, Chicago, Buffalo and Boston.

Once again, he will meet with mayors and church leaders and lead services at local churches.

"If what comes out of this is that Orthodox people feel a sense of unity, we could not have hoped to accomplish more," said Nikki Stephanopoulos, spokesman for the patriarch's visit.