The Trump administration introduced sanctions Friday to prohibit Venezuela's national leaders from accessing U.S. credit or selling bonds to Americans, but specifically and purposefully don't hit the country's oil industry.

Senior administration officials avoided directly answering whether a potential fifth wave of sanctions against the government and its leaders would affect oil exports, a major source of wealth for the South American country.

"What we're trying to do here is create a series of escalatory measures that we can take," one official told reporters during a call organized by the White House.

"Obviously the U.S. has a lot of influence over the Venezuelan economy, but it doesn't mean we want to go rush in and use our influence in an irresponsible manner," they said when asked about oil.

The new sanctions are aimed at putting pressure on the government of socialist President Nicolas Maduro, after he assembled a Constituent Assembly to bypass the opposition-controlled National Assembly as the economy tanks amid massive protests.

The sanctions restrict debt restructuring by the state oil company PDVSA, but do not block the company from accessing U.S. credit for fuel transportation. "This was done very deliberately," one official said, by allowing short-term debt.

Citgo, the Venezuela-owned company that runs a large number of U.S. gas stations, is treated specially, officials said. The company will be allowed to continue to access U.S. credit, an official said, but distribution of dividends or other profit-sharing will be limited.

"This is a preemptive measure to ensure the Maduro dictatorship does not subsequently loot Citgo as these measures go into effect," one official said. The U.S.-based company last year became 49.9 percent owned by Russia's state-controlled Rosneft, which is also the subject of separate U.S. sanctions.

"There are multiple provisions that exist to allow Citgo to continue its business operations and make sure the regime does not loot them to sustain its campaign of repression," one official said.

"No, this is not an oil embargo, in fact we specifically provide flexibility to allow transactions in the oil sector to continue, that's why the 90-day rule on PDVSA debt is allowed," an official told reporters.

They added: "This is a prohibition on the Maduro regime accessing U.S. capital markets for the purpose of underwriting its repression of the Venezuelan people."