U.S. President Donald Trump signed an executive order that prohibits dealings in new Venezuelan government debt and state oil company debt in an effort to pressure President Nicolas Maduro’s “dictatorship” to halt its “tyranny,” the White House said on Friday.

The order marks a significant escalation in recent sanctions imposed by Washington against Maduro and senior officials in his government to punish them for what the Trump administration sees as their role in undermining democracy in the oil-producing country.

“These measures are carefully calibrated to deny the Maduro dictatorship a critical source of financing to maintain its illegitimate rule, protect the United States financial system from complicity in Venezuela’s corruption and in the impoverishment of the Venezuelan people,” the White House said in a statement.

“We will not stand by as Venezuela crumbles,” it said.

The executive order prohibits dealings in new debt and equity issued by the Venezuelan government and its state-run oil company PDVSA as well as in some existing bonds owned by the public sector. It also prohibits payment of dividends to the Venezuelan government, the White House said.

While the executive order protects holders of many existing Venezuelan government and PDVSA bonds, it will make the refinancing of PDVSA’s hefty debt burden difficult and could further push the country toward financing from Russia and China.

Yields on Venezuela’s benchmark 2038 sovereign bond and those of state-run oil company PDVSA’s benchmark 2037 bond rose modestly after the announcement of the latest round of U.S. sanctions.

“Without a doubt restructuring and swaps are no longer possible now,” said a broker in Venezuela.

Some bondholders expressed relief that the measures were not a widespread ban on trading of existing bonds.

Trump's order allows the U.S. Treasury to provide licenses for dealings in select existing Venezuelan debts and many commercial and humanitarian transactions, including those for commercial trade and petroleum trade as well as for transactions involving only PDVSA's U.S. unit, Citgo Petroleum.

Washington on Aug. 9 imposed sanctions against eight individuals, including the brother of late socialist leader Hugo Chavez.