Secretary of State Rex Tillerson's hesitance to tap into a fund for countering Russian and terrorist propaganda is drawing bipartisan Senate criticism.

A pair of lawmakers urged Tillerson to make use of about $80 million authorized for spending to counter disinformation campaigns launched by American enemies. Tillerson's team says the State Department lacks an effective plan for the program, but anonymous diplomatic critics claim that Tillerson worries about upsetting Russia.

The senators joined the chorus by echoing the need for Tillerson to ramp up the messaging efforts.

"It is very concerning that progress on combatting this problem is being delayed because the State Department isn't tapping into these resources," Sen. Rob Portman, R-Ohio, a Foreign Relations Committee member who co-authored legislation enhancing counter-propaganda efforts in 2016.

"The State Department should take swift action to fully fund the [Global Engagement Center] and ensure that it is capable of carrying out the purposes Congress directed, particularly as they relate to Russia and other state-sponsored foreign disinformation."

Tillerson's team has held up the spending, at risk of losing access to the money when the current government spending plan ends on Sept. 30, citing the need for a plan for the program.

"They put in a request in for additional funding," Tillerson spokesman R.C. Hammond told Politico to explain the delays. "We asked them to map out a plan of how they would spend the money. ... We have not sought to reduce efforts to spotlight and combat Moscow's 'active measures' or information activities."

That was disputed by a unnamed former State Department official, who said Hammond was motivated at least in part by a desire to avoid aggravating Russia, which opposes the program.

"Hammond said the secretary is in the process of working through disagreements with Russia, and this is not consistent with what we're trying to do," the official said in the report.

The senators avoided commenting on Tillerson's possible motives, but they faulted his team for having failed to request the money Congress authorized for the Global Engagement Center.

"This is indefensible," Sen. Chris Murphy, the Connecticut Democrat who co-authored the bill with Portman, said Wednesday. "Every day, ISIS is spreading terrorist propaganda, and Russia is implementing a sophisticated disinformation campaign to undermine the United States and our allies. ... I strongly urge Secretary Tillerson to take this issue seriously and use the tools and resources he has at his disposal to stand up to our adversaries."