The U.S. and Mexico failed to reach a deal on immigration issues during their Wednesday meeting.

Officials met just days before 5% tariffs on all Mexican imports are set to kick in, while President Donald Trump was in the U.K. on a state visit. Trump announced the tariffs in a surprise tweet last Thursday, saying they would be imposed "until such time as illegal migrants coming through Mexico, and into our Country, STOP."

On Wednesday evening, Trump tweeted that "progress is being made, but not nearly enough!" The president said talks will continue on Thursday and that if no deal is reached then tariffs will begin on Monday.

@realDonaldTrump: Immigration discussions at the White House with representatives of Mexico have ended for the day. Progress is being made, but not nearly enough! Border arrests for May are at 133,000 because of Mexico & the Democrats in Congress refusing to budge on immigration reform. Further...

@realDonaldTrump: ....talks with Mexico will resume tomorrow with the understanding that, if no agreement is reached, Tariffs at the 5% level will begin on Monday, with monthly increases as per schedule. The higher the Tariffs go, the higher the number of companies that will move back to the USA!

Mexican Foreign Secretary Marcelo Ebrard told reporters that tariffs were not discussed during Wednesday's meeting and confirmed talks will continue Thursday. He said the conversation focused on migration.

The outcome was not entirely unexpected, despite White House trade advisor Peter Navarro's remark earlier Wednesday that Trump's tariff threat had gotten Mexico's attention. A senior administration official told CNBC hours before the talks began that they were being viewed as a starting line for negotiations between the two countries, not a finish line.

The Trump administration threatens to steadily hike those tariffs up to 25% by October unless Mexico stems the flow of migrants coming to the U.S. southern border illegally.

@realDonaldTrump: On June 10th, the United States will impose a 5% Tariff on all goods coming into our Country from Mexico, until such time as illegal migrants coming through Mexico, and into our Country, STOP. The Tariff will gradually increase until the Illegal Immigration problem is remedied,..

In a White House statement released shortly after the initial threat, however, Trump said that "If the illegal migration crisis is alleviated through effective actions taken by Mexico, to be determined in our sole discretion and judgment, the Tariffs will be removed."

Hours before the Mexican delegation arrived at the White House for the talks Wednesday, Navarro said the tariffs "may not have to go into effect at all" if Mexico agreed to make certain concessions during the talks.

Navarro said Mexico would need to crack down on asylum seekers, strengthen enforcement of its own southern border with Guatemala and address government corruption at Mexican immigration checkpoints.

Mexican officials have argued that these tariffs would be counterproductive and that the country has already taken steps to address migration issues.