STOCKHOLM (Reuters) - The Nobel Foundation said on Saturday it would not after all invite the ambassadors of Russia, Belarus and Iran to attend the Nobel Prize awards ceremony in Stockholm this year, reversing an earlier decision after widespread criticism.

Last year, the foundation left out the ambassadors of Russia and its ally Belarus because of Moscow's invasion of Ukraine.

The foundation said on Thursday it would invite them, and Iran's ambassador, to this year's prize award ceremonies in December, commenting that it sought to include even those who did not share the values of the Nobel Prize.

That announcement prompted the leaders of several Swedish political parties to say they would boycott the ceremonies.

"We recognise the strong reactions in Sweden," the foundation said in a statement on Saturday.

"We, therefore, choose to repeat last year's exception to regular practice – that is, to not invite the ambassadors of Russia, Belarus and Iran to the Nobel Prize award ceremony in Stockholm."

The prize-winners are announced in early October and five of the six Nobel prizes are awarded in Stockholm every year after a nomination process that is kept secret for the next 50 years. The Nobel Peace Prize is awarded in Oslo where separate festivities are held.

(Reporting by Simon Johnson; Editing by Frances Kerry)