Russia has withdrawn key defense advisers from Venezuela, an embarrassment for President Nicolás Maduro as Moscow weighs the leader’s political and economic resilience against growing U.S. pressure, reports Fox News.

Russian state defense contractor Rostec, which has trained Venezuelan troops and advised on securing arms contracts, has cut its staff in Venezuela to just a few dozen, from about 1,000 at the height of cooperation between Moscow and Caracas several years ago, said a person close to the Russian defense ministry.

The gradual pullout, which has escalated over the last several months, according to people familiar with the situation, is due to a lack of new contracts and the acceptance that Mr. Maduro’s regime no longer has the cash to continue to pay for other Rostec services associated with past contracts.

Russia has been among Maduro’s biggest international supporters, but the winding down of Rostec’s presence shows the limits of Russia’s reach in the South American country at a time when Moscow is facing economic difficulties—in part due to the impact of U.S. sanctions—at home. Venezuela has been one of Moscow’s largest customers in South America.