DENVER -- Colorado's Democratic Party leaders are refusing to extend a deadline for members who failed to fill out a form allowing them to run as national delegates to the Democratic National Convention.

Sherry Jackson, the state party's executive director, said most of the party members who have called to complain about missing the deadline are Barack Obama supporters.

Jackson said the party did what it could to notify members about the April registration deadline. The presidential campaigns were supposed to follow up to ensure that their supporters got to Colorado's Feb. 5 caucuses and complete the form to allow them to become candidates for national delegates.

"We're not to blame," Jackson said.

State party chairwoman Pat Waak said the April deadline for DNC candidate registration was stressed "every step of the way."

Party member Josh Brodbeck said he assumed that because he was an Obama delegate to the state convention he was automatically a candidate for becoming a DNC delegate. He said more should have been done.

Longtime party members say that every four years they hear from delegates who complain that they didn't know they had to fill out a separate registration form to run as a DNC delegate.

The national convention will be held Aug. 25-28 in Denver.