US President Donald Trump and British Prime Minister Theresa May have reaffirmed their commitment to the Nato alliance after White House talks.
Mrs May confirmed Mr Trump was "100% behind Nato" despite the president's recent comments calling the transatlantic alliance obsolete.
Both leaders said they would work to establish trade negotiation agreements.
Mrs May also said Mr Trump had accepted an invitation from the Queen for a state visit later this year.
"Great days lie ahead for our two peoples and our two countries," Mr Trump said.
The prime minister added that a trade agreement between the UK and US was "in the national interest in both our countries".
Although the UK cannot begin to negotiate trade deals until it leaves the EU, Mr Trump has said he wants a "quick" deal after that.
When asked about Mr Trump's scheduled phone call with Russian President Vladimir Putin on Saturday, the president played down any suggestion that he would lift US sanctions against the Kremlin.
"It's very early to be talking about that," he told reporters during a news conference.
By Laura Kuenssberg, BBC political editor
If they wanted to display closeness - the image of Theresa May hand in hand with Donald Trump could hardly have been more useful for Downing Street.
Sources in government were delighted that she visibly forced out a 100% commitment from him to Nato, the more experienced politician perhaps, the formal, next to the flash.
The relationship between any prime minister and any president is always important. But with Britain stepping back from its European ties, the bonds across the Atlantic become only more vital.
Theresa May's presence seemed to bring out a more restrained Donald Trump. Could she be building an image, a role, as a good influence on the rogue president?
This is a high wire act. For hitching her own political fortunes to president Trump, praising his "stunning victory", gambles that he will not crash and burn as president, gambles that those concerned about his beliefs at home, will not be repelled by her overtures to the new leader.
Only a perverse British prime minister would not try to build a good relationship with an American leader. But Theresa May's host is a new kind of president. The pressure this new political friendship could put on her will be new too.
He also said having a "great relationship" with countries like Russia and China "would be a positive, not a negative".
Meanwhile, Mrs May stood firm with the European Union's stance on sanctions against Russia.
"We have been very clear that we want to see the Minsk agreement fully implemented," she said, adding that the sanctions would continue until that is achieved.
Mr Trump said he would also defer to retired general and Defense Secretary James Mattis on whether he would reinstate the use of waterboarding as an interrogation technique.
The president said Mr Mattis does not "necessarily believe" in waterboarding and other interrogation techniques, which critics view as torture.
"I don't necessarily agree, but I would tell you that he will override because I'm giving him that power," Mr Trump said of General Mattis.
"I happen to feel that it does work. I've been open about that for a long period of time. But I am going with our leaders."
Also on Friday, at the end of Mr Trump's first week in power, he:
- sent a message of support to anti-abortion activists holding a large rally in Washington
- is expected to sign an executive order restricting refugee entry to the US
- held an hour-long phone call with Mexican President Enrique Pena Nieto to repair relations that have soured over the border wall plan
- called the media the "opposition party" in an interview with Christian Broadcast Network
Asked about how well he got along with the British prime minister, he joked: "I'm not as brash as you might think."
And Mrs May said the two of them share a political approach of putting "the interests of ordinary people" first, reaffirming the US and UK's longstanding "special relationship".
The president also boasted about Brexit, calling it a "wonderful thing".
He contended that was "scorned" by media for predicting Brexit during a visit to Scotland, the day before the vote.
But Twitter users were quick to point out that when in the UK, Mr Trump spoke to the media a day after the EU referendum.
Earlier, the two leaders posed for photographs in front of a bust of Sir Winston Churchill - which Mr Trump pointed to, saying it was "a great honour" to have it back.
The new president had the bust restored to the Oval Office after it was removed by former president Barack Obama.
Mrs May smiled and told him: "Thank you, we were very pleased that you accepted it back."