Donald Trump's state visit to the UK is in fresh doubt after there was no mention of it in the Queen's Speech.
The US president accepted the Queen's invitation for him to travel to Britain when Prime Minister Theresa May visited Washington in January.
There have been reports that Mr Trump has changed his mind and does not want to visit while there is potential for protests against him.
But a Trump official told the BBC: "The two governments are discussing dates."
Number 10 said the Queen had not mentioned the visit because no date had been set.
Wednesday's Queen's Speech at the State Opening of Parliament saw the monarch announce the government's legislative programme for the next two years.
The Queen also uses the speech to set out her official plans for the year.
She said she looked forward to welcoming King Felipe VI and Queen Letizia of Spain for their state visit in July, and hosting the Commonwealth summit in April next year.
But there was no word about Mr Trump's state visit. October had been suggested as a possible date.
A Downing Street spokesman said: "An invitation has been extended and accepted.
"The visit wasn't mentioned in the Queen's Speech because a date hasn't been fixed yet."
In his last statement on the issue, White House spokesman Sean Spicer had said: "Her Majesty extended an invitation to the president. He's accepted that invitation. And we look forward to scheduling that trip.
"There is nothing that was scheduled and we look forward to working out a mutually acceptable date with the United Kingdom, and look forward to sharing that date."
By James Landale, diplomatic correspondent
There is a very good reason for that date not being set. That is because there are concerns within the White House that if Donald Trump came to the UK, there would be some substantial protests.
There is also a concern within the British government that it would not help US-UK relations if the US president was embarrassed.
It is very unlikely he will be coming this year.
This government has only so much bandwidth, that trying to work out precisely when they are going to have a visit from the US president, particularly if he is having cold feet, is something I imagine they will say to put on the back burner for a bit.
When the invitation was first made by Theresa May on behalf of the Queen, there was a lot of concern that she had jumped the gun and gone too fast on this - to give a new US president the offer of a full state visit was a little premature.
Normally that kind of offer does not come until well into the presidency. It quite often happens in a president's second term - if re-elected - and not all US presidents get full state visits.
So the fact that it is going to be delayed will not come as a huge disappointment to many people who thought it was a little bit too much, too early.