Britain and Turkey have ordered millions of COVID-19 vaccines as they boost supplies to fight the pandemic.
The UK will buy 60 million more doses of Pfizer/BioNTech's vaccine, health minister Matt Hancock says, in a deal that more than doubles the country's supply of the shot.
Britain has now ordered a total of 100 million doses of the Pfizer vaccine, one of three COVID-19 shots being rolled out in the country.
Hancock said the shots had been secured to support a booster vaccination programme starting in the UK autumn, adding that the biggest risk to Britain's rollout so far was a new variant of the coronavirus.
Britain has administered 47.5 million vaccine doses so far, nearly 34 million of which are first shots.
While the country is second only to Israel in terms of the proportion of the population who have received a first dose, which stands at around 50 per cent, it has suffered 127,000 deaths from COVID-19, the fifth-highest total globally.
Britain, which has a population of 67 million, has deals for 517 million doses of eight different COVID-19 vaccines, some of which remain under development.
Meanwhile Turkey on Wednesday signed a deal for 50 million doses of Russia's Sputnik V COVID-19 vaccine that will start arriving next month.
Health Minister Fahrettin Koca said it should help address a short-term fall in supply.
Vaccines will be scarce in the upcoming two months, Koca said, but the shortfall should in time be overcome with the new procurements and ultimately by production in Turkey.
"We are at the last stage for Sputnik V vaccine emergency use authorisation," Koca said in a televised speech.
"Turkey signed a deal to receive 50 million doses within six months."
Turkey has until now been using COVID-19 vaccines developed by China's Sinovac Biotech Ltd and by Pfizer and BioNTech.
It has carried out 22 million inoculations, with 13.55 million people having received a first dose.
On Monday, the Russian Direct Investment Fund (RDIF) said a Turkish pharmaceutical firms would also produce Sputnik V COVID-19 vaccine at its plants.