U.S. intelligence officers say they have reason to believe as many as 50 undercover Russian citizens tried to register to attend the Texas Democratic Convention in what appears to be the first known attempt to meddle in the 2018 election, according to a report published Thursday.

"In the context of what we already know, the Texas case points to the broader Russian effort," one senior intelligence official told NBC.

Exactly four dozen people tried to register for the Austin, Texas, convention and are not residents of Travis County or even Texas.

The group of wannabe attendees are also not American citizens and their attempt to go to the convention is similar to previous Russian attempts to sneak into other U.S. election-related events, two current and three former senior intelligence officers told NBC.

Event officials in Austin say they made an unusual discovery earlier this year after noticing a number of applications to attend were not completely filled out or contained information that was obviously false.

Twenty-five of the applications contained email addresses that ended with "mail.ru," which indicates the online message was sent from a domain in Russia. Of those 25, all appear to be affiliated with an actual person, meaning they are not "bot" accounts.

Glen Maxey, legislative affairs director of the Texas Democratic Party, said he did not know who to inform of his findings and worried about what other counties, even larger cities, may be seeing.

"If things like this appear to be happening in small county registration systems in Texas, what could that mean for other parts of the country?" Maxey said.

One intelligence official said the Texas incident indicates whoever is behind it is focused on attacking a political party, not the voter registration system in general. The official explained it would be easier to go after organizations than "systems that state officials and homeland security are now prepared to defend."

However, Maxey said he does not know who to reach out to in the state government, which was why he contacted a news outlet.

"Who would I report political interference to?" Maxey said. "There has been no guidance of any kind from the feds or the state."