US President Donald Trump has said “not nearly enough” progress is being made in negotiations with Mexico to avert his threatened tariffs.
Trump administration officials hosted Mexico’s foreign minister at the White House on Wednesday, and they will meet again on Thursday.
Mr Trump said import duties of 5% will take effect next Monday unless Mexico stems the migrant flow into the US.
Those numbers reached their highest level in more than a decade last month.
What happened in the negotiations?
US Vice-President Mike Pence and Secretary of State Mike Pompeo held talks with Mexican Foreign Minister Marcelo Ebrard at the White House on Wednesday, but the meeting ended without agreement.
Mr Ebrard told a news conference afterwards that tariffs were not even discussed.
“The dialogue was focused on migration flows and what Mexico is doing or is proposing to the United States, our concern about the Central American situation,” he said.
The US president, who is in Europe for World War Two commemorations, warned on Twitter that the tariffs would go ahead next Monday without a breakthrough.
Republican senators have been speaking out against the planned Mexico tariffs, which Mr Trump announced last week on Twitter, catching his party and the financial markets unawares.
Under his proposal, duties would rise by 5% every month on goods including cars, beer, tequila, fruit and vegetables, reaching 25% by October.
The Republican president wants Mexico to stop the hundreds of thousands of mostly Central American migrants who have been seeking entry to the US this year.
White House trade adviser Peter Navarro had raised hopes earlier on Wednesday of a possible rapprochement.
He told CNN “we believe that these tariffs may not have to go into effect, precisely because we have the Mexicans’ attention”.
Mr Navarro said Mr Trump wants Mexico to commit to take all asylum seekers and to divert more resources to its own southern border with Guatemala.
America is already embattled in a trade war with China that has seen tit-for-tat duties imposed on imports.
What’s the situation on the US-Mexico border?
The stakes were raised on Wednesday as US Customs and Border Protection announced that migrant arrests had surged in May to the highest level in more than a decade.
Border Patrol apprehended 132,887 migrants attempting to enter the US from Mexico in May, marking a 33% increase from the month before.
It said 84,542 were families and 11,507 unaccompanied children.
The arrests were the highest monthly total since Mr Trump took office.
Another 11,391 migrants were deemed “inadmissible” and turned away after arriving at US ports of entry, bringing the overall figure to 144,278.
“We are in a full-blown emergency, and I cannot say this stronger, the system is broken,” said acting CBP Commissioner John Sanders.
How do the numbers compare with previous years?
Official figures show illegal border crossings have been in decline since 2000.
In 2000, 1.6 million people were apprehended trying to cross the border illegally – that number was just under 400,000 in 2018.
In 2017, Mr Trump’s first year in office, the figures were the lowest they had been since 1971.
The decline was in large part due to a dip in the number of people coming from Mexico.
In the last two years, however, the number of arrests has been rising again, especially in recent months.