Theresa May has criticised Donald Trump's immigration policy, saying she finds pictures of child migrants being kept in cages in the US "deeply distrubing".
She called the detention policy "wrong" and "not something we agree with".
Mr Trump has defended migrant families being split up and young children being kept in cages as part of a controversial clampdown on illegal immigration.
Challenged by the SNP's Ian Blackford to condemn the move, Mrs May told the House of Commons on Wednesday: "The pictures of children being held in what appear to be cages are deeply disturbing.
:: Donald Trump's migrant border row explained
"This is wrong, this is not something we agree with, this is not the UK's approach.
"When I was Home Secretary, I ended the routine detention of families with children."
She also said the UK had a "special, long-standing relationship with the US" and that there were "a range of issues" she would discuss with Mr Trump.
Looking ahead to his visit to Britain next month, Mrs May added: "It's important that when we see the president of the US here in the UK, we're able to have those discussions that means when we disagree with what they're doing, we say so."
:: Backlash after Fox News 'summer camps' migration comment
Tougher action at the US-Mexico border was one of the central planks of Mr Trump's election campaign.
His administration has adopted a "zero-tolerance" policy for anyone caught illegally entering the country.
Now, everyone who makes their way over the border is referred for prosecution.
According to US Customs and Border Protection, as many as 1,500 people are arrested every day.
More from Politics
Adults are sent to the custody of the US Marshals Service, while children are sent to facilities run by the health and human services department, because children cannot go to federal jail.
Between 5 May and 9 June, about 2,300 children were separated from their parents.
Theresa May has criticised Donald Trump's immigration policy, saying she finds pictures of child migrants being kept in cages in the US "deeply distrubing".
She called the detention policy "wrong" and "not something we agree with".
Mr Trump has defended migrant families being split up and young children being kept in cages as part of a controversial clampdown on illegal immigration.
Challenged by the SNP's Ian Blackford to condemn the move, Mrs May told the House of Commons on Wednesday: "The pictures of children being held in what appear to be cages are deeply disturbing.
:: Donald Trump's migrant border row explained
"This is wrong, this is not something we agree with, this is not the UK's approach.
"When I was Home Secretary, I ended the routine detention of families with children."
She also said the UK had a "special, long-standing relationship with the US" and that there were "a range of issues" she would discuss with Mr Trump.
Looking ahead to his visit to Britain next month, Mrs May added: "It's important that when we see the president of the US here in the UK, we're able to have those discussions that means when we disagree with what they're doing, we say so."
:: Backlash after Fox News 'summer camps' migration comment
Tougher action at the US-Mexico border was one of the central planks of Mr Trump's election campaign.
His administration has adopted a "zero-tolerance" policy for anyone caught illegally entering the country.
Now, everyone who makes their way over the border is referred for prosecution.
According to US Customs and Border Protection, as many as 1,500 people are arrested every day.
More from Politics
Adults are sent to the custody of the US Marshals Service, while children are sent to facilities run by the health and human services department, because children cannot go to federal jail.
Between 5 May and 9 June, about 2,300 children were separated from their parents.
