Amid controversies surrounding the nation's procurement of COVID-19 vaccine, Health Secretary Francisco Duque III warned that the use of unregulated drugs and vaccines is illegal while sanctions await medical professionals administering these.

In a statement on Thursday, Duque said any medications to be used against the dreaded respiratory disease should be approved first by the Food and Drug Administration (FDA) or these will be deemed illegal.

"Our frontliners have been struggling with the rising cases from the beginning. This will only make the situation worse. The risks cannot be denied and may even prove fatal to some," Duque said.

The DOH chief added that they will probe the unauthorized administration of smuggled vaccines, as well as doctors and other medical professionals who administer them. 

"We will have their medical licenses revoked. We doctors have an oath. Do no harm. In a pandemic, we need to be more circumspect," he emphasized.

Duque made the warning following rumors regarding legislators who are allegedly getting their COVID-19 vaccines illegally.

"I'm not buying the explanation that the doctors administering the shots are being pressured by lawmakers. Someone is peddling the service and it is unacceptable," he added.

Meanwhile, FDA director general Enrique Domingo said they already received Pfizer's application for emergency use authorization before Christmas and it is currently under evaluation.

"We understand the urgency of the situation and we are carefully reviewing the documents they submitted and taking into account the possible risks to the public. We will make a decision at the soonest possible time," he said.

Domingo noted that the FDA and the DOH are working closely with the Bureau of Customs to prevent the entry of unauthorized COVID-19 vaccines and other drugs in the country.

"We have sent our enforcement unit to the field and we are awaiting the report. We are fully committed to monitoring this," Domingo said.