Boris Johnson has warned against the placing of restrictions on COVID vaccines after the EU threatened to put controls on the export of doses to Britain.
The prime minister, speaking at a Downing Street news conference on Tuesday, said he expected the EU to "honour all contracts" in the supply of vaccinations to the UK.
"We fully expect that will happen and we continue to work with friends and partners in the EU and, indeed, around the world," Mr Johnson said.
"Because the delivery of the vaccine has been a multinational effort, the creation of the vaccine has been a multinational effort and the delivery of the vaccine is multinational as well, because the virus knows no borders."
On Monday, EU commissioner Stella Kyriakides warned the bloc would "take any action required to protect its citizens and rights" amid a row over the supply of the AstraZeneca vaccine, which is mainly produced in the UK.
The British-based company recently told the EU the initial number of doses it could supply to the bloc would be lower than first thought, due to manufacturing issues.
Ms Kyriakides criticised the "not acceptable" situation and, additionally, warned that "clarity" and "full transparency" on the export of vaccines from the EU would be demanded.
She said all companies producing COVID vaccines in the EU would now have to provide "early notification" when exporting to third countries.
This has raised fears of restrictions on the supply of the Pfizer vaccine, which is produced in Belgium, to Britain.
The Pfizer vaccine was the first to be used in the UK and the government has ordered 40 million doses of the jab.
At Tuesday's news conference, Mr Johnson said he was aware of Ms Kyriakides's comments but stressed he had "total confidence" in the UK's vaccine supply.
He added: "The creation of these vaccines has been a wonderful example of multinational cooperation.
"One of the lessons the world has to learn from the pandemic is the need to cooperate and to make sure we do things together, and we understand how to fight these pandemics together.
"So I don't want to see restrictions on the supply of PPE across borders, I don't want to see restrictions on the supply of drugs across borders, and I don't want to see restrictions on vaccines or their ingredients across borders.
"I think that's pretty commonsensical and I'm sure it would be widely supported across the EU as well."
Earlier on Tuesday, Health Secretary Matt Hancock urged countries "to be collaborative" in the rollout of vaccines and said that "protectionism is not the right approach in the middle of a pandemic".
"I'm sure that we can work with the EU to ensure that, whilst transparency is welcome, that no blockers are put in
place," he said at an event hosted by Chatham House.
"I'm confident of the supply of vaccine into the UK. I'm confident that won't be disrupted."
Sir Simon Stevens, chief executive of NHS England, told MPs that "of course there is a supply shortage" of coronavirus vaccines.
"If there were unlimited vaccines then you wouldn't see what the European Commission were saying yesterday, you wouldn't see Italy attempting to sue one of the manufacturers, you wouldn't see Germany in uproar as it is today," he told the House of Commons' health committee.
"Of course there's a supply shortage, and we've done very well in this country to get the supply we have available to us, the question is how do we use it to best effect."