Media playback is unsupported on your device Media caption How will President Trump deliver on border wall promise?

Donald Trump has hit out at Mexico after its president cancelled next week's visit to the White House.

The US president said meeting Enrique Pena Nieto would be "fruitless" if Mexico didn't treat the US "with respect" and pay for a new border wall.

The diplomatic spat comes a day after Mr Trump unveiled his plan to build a barrier along the Mexico-US border.

Senate Republicans said the US Congress would move ahead with the plan, and it would cost $12bn (£9.5bn) to $15bn.

Mr Trump told Republican lawmakers in Philadelphia that the two leaders had mutually agreed to cancel the summit, adding, "the American people will not pay for the wall."

"Unless Mexico is going to treat the United States fairly, with respect, such a meeting would be fruitless, and I want to go a different route. We have no choice."

White House spokesman Sean Spicer told reporters they were looking "for a date to reschedule", adding they will "continue to keep the lines of communication open".

Media playback is unsupported on your device Media caption "US to begin building wall immediately"

Mr Pena Nieto announced earlier on Thursday he had called off the 31 January trip after Mr Trump suggested he should do just that.

"If Mexico is unwilling to pay for the badly needed wall, then it would be better to cancel the upcoming meeting," the US president wrote on Twitter on Thursday morning.

In a televised address, Mr Pena Nieto said he "lamented" the plans for the barrier.

The Mexican leader told the nation: "I've said time and again: Mexico won't pay for any wall.

"I regret and condemn the decision of the United States to continue construction of a wall that, for years, has divided us instead of uniting us."

Mr Pena Nieto met Mr Trump - then a presidential candidate - in Mexico City in September and came under intense criticism at home. His approval ratings remain low.

Pena Nieto had no option - Will Grant, BBC News, Mexico City

Mr Nieto is facing the lowest approval ratings of any Mexican president over the past two decades. Much of that unpopularity is down to Donald Trump. Many Mexicans consider their leader lacks the necessary steel to deal with the new Republican president and has been railroaded on everything from the border wall to Nafta.

So when President Trump challenged - some might even say goaded - him to cancel their meeting, Mr Pena Nieto was left with little other option.

He would have been perceived as very weak if he had travelled to Washington for talks and for many here, it would have been tantamount to accepting Mr Trump's central claim - that Mexico will pay for the US border wall. If not up front, then eventually.

That is simply unacceptable to most ordinary Mexicans who view the wall as unnecessary, inhumane, expensive and ineffective.

As their elected leader, at least for the next 18 months, Enrique Pena Nieto was duty-bound to deliver that message to the White House.

Mutually beneficial relationship - John Mervin, BBC business editor, New York

A quick glance at the US Trade Representative's website's explanation of trade with Mexico gives a clear picture of how much the US benefits. Mexico is the third-biggest trading partner of the US. Trade between the two countries is worth nearly $600bn a year.

Mr Trump's fierce criticism of the North America Free Trade Agreement (Nafta) notwithstanding, the Trade Representative's office points out that since Nafta was passed the value of US goods exported to Mexico has increased by 486%.

Nevertheless, given the respective size of their economies, the US is clearly even more important to Mexico, than Mexico is to the US. The US is Mexico's biggest export market by far. And since Nafta was passed the value of its goods sold north of the border has risen by 638%.

There's no doubt that a major breakdown in trade relations would inflict serious damage on Mexico and the US.

On Thursday, US media reported the chief of US Border Patrol is leaving his job.

It is unclear if Mark Morgan, who heads the agency charged with securing US borders, was forced out or resigned.

Building a barrier along the 2,000 mile (3,200km) US boundary with Mexico was one of Mr Trump's key election pledges.

Mexicans were also outraged when Mr Trump described their migrants as murderers and rapists, while launching his campaign in 2015.

Media playback is unsupported on your device Media caption The mayors of New York and Chicago speak out against Mr Trump's targeting of "sanctuary cities"

Trade relations are also fraying after Mr Trump pledged to renegotiate the North American Free Trade Agreement and impose border taxes on US firms that move jobs to Mexico.

As he signed the wall-building directive on Wednesday, Mr Trump warned of a "crisis" on the southern US border.

His executive orders also called for hiring 10,000 immigration officials to help boost border patrol efforts.

Image copyright AFP Image caption Portions of a barrier have already been built on the US-Mexico border

In other developments: