WASHINGTON, Nov 12 (Reuters) - President Donald Trump threatened on Thursday to double tariffs on Mexico ‌if it does not stop more than a thousand migrants walking north toward the United States after last week's US election, warning that they would not be allowed to enter.

"Here we go again!" the Republican president wrote on social media. "They will not be accepted! MEXICO MUST STOP THEM, NOW, and if they do not do ​so, the Tariffs on Mexico will be IMMEDIATELY DOUBLED. MEXICO, THE GOVERNOR OF TEXAS, THE VERY LIBERAL NEW GOVERNOR OF TEXAS, ​OUR GREAT BORDER PATROL, & ICE, HAVE BEEN SO INFORMED. There will be no leniency!"

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Mexican President Claudia Sheinbaum recognized that a group of people were walking northward toward the United States, but said that no migrant caravans have arrived at the US border since Trump returned to power last year.

People in the migrant caravan have been informed of how difficult it is to enter the US, ​and Mexico is looking to return them to their countries of origin, Sheinbaum told a regular press conference.

"There will be no acts of ​repression," Sheinbaum added.

Some local media have reported that authorities in the southern state of Chiapas have turned back migrants as they sought to join the group ‌this week.

Mexico's ⁠migration institute and the Chiapas state government did not immediately respond to requests for comment.

"We will utilize all assets to make sure our borders are secure," US Homeland Security Secretary Markwayne Mullin wrote on social media following Trump's tariff threat. "This illegal migrant caravan will NOT be allowed to enter our country. Full stop."

The United States and Mexico are negotiating a trade agreement after Trump chose in July to not extend the US-Mexico-Canada ​trade pact.

The Trump administration's tough immigration ​policies mostly stopped the flow ⁠of migrants to the US southern border, leaving many Mexican migrant shelters empty.

Trump was elected to a second term as president in 2024 in part over concern among US voters about the border. Since then, Trump ​has highlighted some migrant caravans but also said in recent months the issue has become less politically ​potent for him and ⁠his fellow Republicans.

"I am sure the new governor is going to want to have security at the Texas border," Trump told reporters after the November 3 midterm election, referencing the newly elected Texas governor, Democrat Gina Hinojosa.

Trump also has acknowledged political backlash from his administration's deportation program through US ⁠Immigration and ​Customs Enforcement.

On Sunday, Trump told the CBS program "60 Minutes" that the deportation force had ​been "too tough" and that he was open to making an immigration deal with Democrats after they take control of Congress.

Reporting by Susan Heavey and Bo Erickson in Washington; Additional ​reporting by Paolo Laudani in Gdansk, Ana Isabel Martinez, Lizbeth Diaz and Iñigo Alexander in Mexico City; editing by Doina Chiacu and Will Dunham