LAREDO, Texas — Senator Clinton’s campaign has raised the possibility of a challenge to Texas’s primary and caucus rules just days before the contest, drawing a warning against legal action from the state’s Democratic Party.

Top strategists for a Democratic rival, Senator Obama, said today they supported the party’s action, suggesting the Clinton campaign was trying to block the reporting of caucus results.

Aides to Mrs. Clinton said earlier this week they were alarmed at the lack of clarity about many of the caucus rules and expressed their concerns on a conference call with Mr. Obama’s staff and state party officials. Texas has a two-step voting process, with a primary and then caucuses shortly after the polls close.

Specifically, Clinton aides questioned a provision allowing caucus attendees to vote to move the location if they choose to do so, and whether people who had cast so-called “provisional ballots” in the primary would have their votes counted in the caucus.

They also expressed concern about the automated phone system precinct chairs would use to call in the results of each caucus, saying the party hadn’t yet trained anyone to use the system properly.

A Clinton political director, Guy Cecil, said he asked party officials to spell out the rules in memorandum form and to send them to both campaigns.

“We want to see the results in writing, and we reserve the right to challenge something if we don’t believe it reflects something that was discussed on the call,” he said, insisting that if there were clear problems with how the caucuses were being run, “you are allowed to say something about it.”

Mr. Cecil today denied that the campaign planned to sue the party, which will manage roughly 8,700 caucuses Tuesday evening.

“There were no veiled threats of lawsuits of any kind,” Mr. Cecil said of the conference call.

Mr. Obama’s campaign manager, David Plouffe, said the Clinton campaign was trying to minimize the results of the caucuses. The former first lady and her team have made clear their unhappiness with caucuses, believing that they cater to the hard-core party activists who tend to support Mr. Obama. The Illinois senator has won 13 caucuses so far, while Mrs. Clinton has won just two.

“This takes it to a new level, which is they don’t want the people who are participating in those caucuses to have their results reported in a timely fashion. And I assume that’s a very self-serving decision,” Mr. Plouffe said.

Texas party officials said they believed Mr. Cecil was threatening legal action and wrote a letter to him and to an Obama senior strategist, Steve Hildebrand, reflecting that concern.

“If it is true that litigation is imminent between one or both of your campaigns and the Texas Democratic Party, such action could prove to be a tragedy for a reinvigorated democratic process that is involving a record number of participants here in Texas and across the nation,” a party attorney, Chad Dunn, wrote. “Litigation regarding the TDP could cripple the momentum of a resurging Texas Democratic Party and ultimately the November 2008 election.”

The letter also noted that many of Mrs. Clinton’s senior campaign advisers in Texas had helped to develop the rules governing the state’s caucus system. A Texas party official also noted that President Clinton won the state’s caucuses in 1992 and 1996 following the same rules.

Texas has 193 delegates up for grabs Tuesday. Of those delegates, 126 will come from the primary, and 67 from the caucus.