CARACAS (Reuters) - Venezuela's central bank in April paid $172 million to U.S. bank Citigroup C.N to recover part of the gold it had put up as guarantee in a swap operation, according to two sources familiar with the situation.

Sanctions levied by U.S. President Donald Trump last year bar U.S. banks from carrying out financing operations with Venezuela, meaning such swaps cannot be renewed.

“Citibank got paid,” said a local finance industry source familiar with the negotiation who asked not to be identified.

“The policy is to recover the gold,” added a second source consulted.

The move showed that, despite a broad default on billions of dollars in bonds, Venezuela is meeting some financial commitments, and the government of President Nicolas Maduro is able to transfer funds when it has reason to do so.

Citi declined to comment. The central bank did not respond to an email seeking comment.

The crisis-stricken OPEC nation has for years been carrying out gold swaps with Wall Street banks to boost the liquidity of its international reserves, which have dwindled to their lowest levels in decades as its socialist system implodes.

Gold swaps allow central banks to receive cash from financial institutions in exchange for lending gold during a specific period of time, and central banks can recover the gold if they repay the borrowed funds in time.

Venezuela between 2014 and 2016 used such operations to free up available hard currency because its reserves are dominated by gold holdings. Those swaps will progressively mature by 2021, the sources said.

An opposition legislator last year said Venezuela allowed a similar swap agreement with Deutsche Bank to lapse.

Neither Venezuelan authorities nor the banks involved have released details about the operations or totals of how many such arrangements remain outstanding.

Venezuela and state oil company PDVSA are in default on most of their $60 billion in outstanding bonds, with some $3.6 billion in backed up debt service.

Maduro has at times blamed the situation on U.S. financial sanctions and a conspiracy of global banks to block transfers of Venezuelan funds to foreign accounts.

But Venezuela has completed some payments.

Those include a coupon payment on PDVSA’s 2022 issue known as “hunger bonds” that was almost entirely bought by Goldman Sachs at a heavy discount in an operation highly criticized by Venezuela’s opposition leaders.

At the end of 2017, the central bank reported a 16 percent drop from the year before in the volume of gold reserves, without explaining the decline. The volume of gold dropped by 31 percent the year before.

As of January, Venezuelan gold reserves stood at around 150 tonnes, their lowest level in decades, according to International Monetary Fund data.