NEW YORK — The Washington National Cathedral, the nation’s traditional host of prayer services for presidents and memorial services to mark national tragedies, announced Wednesday that it will now hold weddings for same-sex couples.

The cathedral, a neogothic landmark in northwest Washington, is the seat of the presiding bishop of the Episcopal Church and the Washington diocese. Episcopalians voted at their convention last summer to authorize an official liturgy for blessing same-sex unions, bringing the church in line with other liberal Christian and Jewish denominations that sanction gay marriage.