Russia and Belarus have effectively been banned from the Queen’s funeral over the war in Ukraine.
Neither country will be able to send a representative to the service at Westminster Abbey next Monday.
The head of state in Myanmar, whose military rules are the subject of UK sanctions, will also not be represented, Whitehall officials confirmed.
The state funeral next week will see a host of world leaders travel to London to pay their respects to the UK’s longest-serving monarch, who died last Thursday aged 96.
Around 500 dignitaries from around the world are expected to descend on the capital to pay their respects to the late Queen.
They will join members of the royal family, senior politicians and other key public figures.
The Kremlin confirmed last week that it was “not an option” for Vladimir Putin to attend the ceremony next Monday.
The Russian president did, however, offer his condolences to King Charles, saying his late mother “rightfully enjoyed her subjects’ love and respect as well as authority on the world stage”.
Russia and Belarus have both been sanctioned by the UK government for their role in Putin’s seven-month invasion of Ukraine.
Myanmar is also on the UK’s sanctions list over the alleged atrocities committed against the Rohingya people.
Iran, meanwhile, will only be represented at an ambassadorial level.
Commonwealth leaders Justin Trudeau of Canada, Anthony Albanese of Australia and Jacinda Ardern of New Zealand will make the long journey to the capital, as will US president Joe Biden.
Before next week’s funeral service, the Queen will lie in state from tomorrow at Westminster Hall, the oldest building on the parliamentary estate.
The ancient hall will be open to the public from 5pm on Wednesday for 24 hours a day until it closes at 6.30am on Monday, September 19.
Hundreds of thousands of people are expected to want to pay their respects to the late Queen, with reports that queues could last up to 35 hours.
Downing Street said on Tuesday that it was not aware of any “upper cap” on the number of people able to attend the Queen’s lying in state.
But the prime minister’s official spokesman warned there were likely to be “long queues… running overnight over successive days” and that London would be “extremely busy”.
The late Queen’s coffin will make its way down to London on Tuesday afternoon after it lay at rest at St Giles Cathedral in Edinburgh.
The Scottish government said 26,000 people had viewed the late monarch’s coffin since Monday, and that the queue to see it had now closed.