NEW YORK — Nine biopharmaceutical companies have signed a joint pledge to uphold "high ethical standards," suggesting they won't seek premature government approval for coronavirus vaccines.

In a joint statement, the drug makers said they would only submit the vaccines for approval after demonstrating safety and efficacy through "large, high-quality clinical trials”.

They promised to "always make the safety and well-being of vaccinated individuals our top priority."

The pledge is signed by the chief executives of AstraZeneca, BioNTech, GlaxoSmithKline, Johnson & Johnson, Merck, Moderna, Novavax, Pfizer and Sanofi.

The unusual move comes amid concerns that political pressure to quickly roll out inoculations could undermine public trust in them, potentially deterring people from taking a vaccine.

US President Donald Trump has repeatedly pushed for a quick vaccine timeline.

"(It's) going to be done in a very short period of time — could even have it during the month of October," the US president said at a press briefing on Monday. "We'll have the vaccine soon, maybe before a special date. You know what date I'm talking about."

The pledge also comes just about a week after US Food and Drug Administration Commissioner Dr. Stephen Hahn said in an interview with the Financial Times that the agency could consider emergency use authorization or approval for a coronavirus vaccine before critical Phase 3 trials are complete.

The nine companies on Tuesday wrote that they pledge to "Only submit for approval or emergency use authorization after demonstrating safety and efficacy through a Phase 3 clinical study that is designed and conducted to meet requirements of expert regulatory authorities such as FDA." — Agencies