PITTSBURGH — Episcopal leaders went to court Thursday seeking control of $20 million in diocesan assets from a conservative group that split from the national denomination last fall.

The Diocese of Pittsburgh, which oversees the 20 local parishes that stayed with the U.S. Episcopal Church, said the breakaway group has no legal right to the assets since it is no longer part of the denomination.

The breakaway conservatives, who also call themselves the Episcopal Diocese of Pittsburgh, said they have a right to some of the assets because they helped develop them before the split.

"We would love to sit down and work out a mediated division where everyone involved has access to a portion of the assets because we think that's fair," said the Rev. Peter Frank, a spokesman for the conservative diocese.

The break was led by former Episcopal Bishop Robert Duncan, a theological conservative who had long been angered by the liberal direction of the national church.

He said he had to split from denominational leaders after Episcopalians in 2003 consecrated the first openly gay bishop, V. Gene Robinson of New Hampshire.

Fifty Pittsburgh conservative Episcopal parishes left with Duncan.

The assets at stake include diocesan endowments and bank accounts, along with insurance, mailing lists and databases, said Rich Creehan, a spokesman for the parishes who filed the legal claim, which does not cover buildings or land.

The case centers on interpretation of a 2005 court order that was issued during earlier litigation between one local parish, Calvary Episcopal Church, and the diocese then led by Duncan.