CARACAS, April 2 (Xinhua) -- U.S. sanctions are cutting off Venezuela's access to vital medical supplies, including an 18-million-euro (20-million-U.S.-dollar) shipment of medicines and vaccines, Venezuela's Health Minister Carlos Alvarado said on Tuesday.

The government has already agreed to purchase the supplies but is unable to pay for them due to Washington's "coercive unilateral" sanctions, Alvarado told state-run VTV.

The purchase includes two million euros' worth of vaccines acquired through international public health agency the Pan American Health Organization, which the government has not been able to pay for because U.S. sanctions have blocked banking transactions, he said.

It's not just medications and vaccines that are in short supply due to the sanctions. "We have many other things that are already negotiated and bought, but the money is blocked and that's why we can't make the payment," said Alvarado.

The South American country has seen its access to medical supplies limited since 2014, when then U.S. President Barack Obama issued an executive order that labeled Venezuela "an unusual and extraordinary threat" to national security, Alvarado recalled.

The situation has been worsening over these years, the minister said, adding that "2017 was the most terrible, most critical period because it was increasingly difficult to buy medicine and to buy vaccines."

As a result, "diseases that had been brought under control in the country, like measles and diphtheria," began to reemerge, he said.