Young people have been asked by President Barack Obama to “reject pessimism and cynicism” and be aware that it is possible to progress and solve problems.
He was in London where he said that “Take a longer, more optimistic view of history.”
Earlier on, the American president also visited the Globe theatre where he watched the performance of actors from Hemlet.
This has happened after his statement that Britain will be at “the back of the queue” while trading with the US if it left the European Union.
The Leave campaigners have been angered by his commands. The leader of UKIP, Nigel Farage, accused him and said that he is taking Britain down.
Mr. Obama also met with the leader of the Labour party, Jeremy Corbyn.
Mr Corbyn said he had had an “excellent” discussion with the president, adding that Mr Obama had congratulated him on being elected leader of his party.
While answering questions of the young people, the US president said that “If any of you begin to work on an issue that you care deeply about, don’t be disappointed if a year out things haven’t been completely solved.
“Don’t give up and succumb to cynicism if after five years poverty has not been eradicated and we haven’t resolved all of the steps we need to take to reverse climate change.”
He added that progress is inevitable.
When he was asked about the attitude towards Muslims, he said that it is a challenge to keep US and UK at peace free from terrorist attacks.
The US president said there was “a tiny subset of groups that have perverted Islam” and our “greatest allies” in tackling extremism in the US were those “Muslim Americans who are historically fully integrated in our society”.
Mr. Obama has intervened into the EU issue just a few weeks before the referendum to determine if to stay or leave the union on 23rd June.
Mr. Obama and Mr. Cameron held a joint conference in which he said that the US is after the growth of Britain and Europe.
“The UK is at its best when it’s helping to lead a strong European Union. It leverages UK power to be part of the EU.
“I don’t think the EU moderates British influence in the world, it magnifies it.”