People should still get their Covid vaccine despite several EU countries pausing use of the Oxford-AstraZeneca jab amid concern about blood clots, the UK medicines regulator has said.
The Medicines and Healthcare products Regulatory Agency said evidence "does not suggest" the jab causes clots.
The Netherlands has become the latest country to suspend use of the jab following reports of serious clotting.
But the World Health Organization says there is no reason to stop using it.
Dutch officials said the move was precautionary following reports from Denmark and Norway about side effects including blood clots.
Manufacturer AstraZeneca has said there is no evidence of a link between the two.
Dr Phil Bryan, vaccines safety lead at the Medicines and Healthcare products Regulatory Agency (MHRA), said people "should still go and get their Covid-19 vaccine when asked to do so."
"We are closely reviewing reports but given the large number of doses administered, and the frequency at which blood clots can occur naturally, the evidence available does not suggest the vaccine is the cause."
Prof Andrew Pollard, director of the Oxford vaccine group, said there were "huge risks" from Covid and vaccination saved lives.
"It's absolutely critical that we don't have a problem of not vaccinating people and have the balance of a huge risk - a known risk of Covid - against what appears so far from the data that we've got from the regulators - no signal of a problem."
He added there was "very reassuring evidence that there is no increase in a blood clot phenomenon here in the UK, where most of the doses in Europe been given so far"
The European Medicines Agency (EMA), which is carrying out a review into incidents of blood clots, said the vaccine's benefits continue to outweigh its risks.
The EMA said that, as of 10 March, there were just 30 reports of clots among almost five million people given the vaccine across Europe.
The Republic of Ireland, Bulgaria, Denmark, Norway and Iceland have paused its use, as has Thailand.
Italy and Austria have stopped using certain batches of the drug as a precautionary measure.
Health officials in Northern Ireland have said they will continue to use the vaccine.
AstraZeneca's chief medical officer Ann Taylor said the number of cases of blood clots reported is lower than the hundreds of cases that would be expected among the general population.
About 17 million people in the EU and the UK have received a dose of the Oxford-AstraZeneca vaccine, manufacturers said.
AstraZeneca said its review had found no evidence of an increased risk of pulmonary embolism, deep vein thrombosis or thrombocytopenia, in any defined age group, gender, batch or in any particular country.
Dr Taylor said: "The nature of the pandemic has led to increased attention in individual cases and we are going beyond the standard practices for safety monitoring of licensed medicines in reporting vaccine events, to ensure public safety."
More than 24 million people in the UK have received the first dose of a coronavirus vaccine, according to government figures.