(CNN) President Donald Trump's anger over Attorney General Jeff Sessions' job performance at the border is tied to complaints made by several senior administration officials, according to a White House official close to discussions on immigration policy.

The official tells CNN Trump has heard directly from high-ranking figures who are upset over the pace at which the Department of Justice has moved to adjudicate asylum claims, resulting in a backlog of cases.

The official says while this is likely "palace intrigue" because the Justice Department "is doing their part," the complaints have only compounded Trump's frustration about a stalled immigration agenda and his anger with Sessions that stems from his decision to recuse himself from the Russia probe last year.

In response, a Justice Department official told CNN that the DOJ is only partly responsible for the backlog and the department has announced the steps it is taking to help reduce it.

There is a massive backlog in immigration courts that is up to hundreds of thousands of cases.

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