After more than three years of threats by President Donald Trump to close the US border with Mexico over illegal immigration and narcotics smuggling, now Mexican officials are contemplating restrictions or monitoring of Southbound traffic due to the spread of the coronavirus in the US.

Mexico has only reported 12 confirmed cases of the COVID-19 virus and no related deaths, compared to the 1,829 confirmed cases and 41 related deaths in the US, making Mexico one of the countries with the lowest cases of the rapidly-spreading virus.

Mexico’s Deputy Health Minister, Hugo Lopez-Gatell, said on Friday that his country is concerned about iinfections from the US.

“If it were technically necessary to consider mechanisms of restriction or stronger surveillance we would have to take into account not that Mexico would bring the virus to the United States, rather that the United States could bring it here,” Lopez-Gatell said during a news conference held in Mexico City.

The threat of the coronavirus spreading across the border is highest among large border regions like San Diego, where more than 50 million people cross between San Diego and Tijuana each year. Many people cross the border from Mexico daily for work, school, and shopping in the US, and could carry an infection back with them, even without knowing they are contagious.

US Ambassador to Mexico, Christopher Landau, met with Mexican lawmakers in Mexico City this week and called for continued cooperation between the countries a range of issues, including organized crime and illegal immigration , as well as health issues like the coronavirus.

“For both countries, it doesn’t benefit us to have completely open borders,” Ambassador Landau said. “We see it now with the virus, and hopefully we can work closely together because in health issues, political parties and borders aren’t important.”

President Trump this week again called for a border wall that has been a centerpiece of policies toward Mexico since he first launched his campaign for president in 2015, arguing that restricting movement across the border is now needed “more than ever” as the coronavirus spreads.

“To this point, and because we have had a very strong border policy, we have had 40 deaths related to Coronavirus,” Trump wrote in a Twitter message on Friday. “If we had weak or open borders, that number would be many times higher!”

Trump has not suggested building a wall or restricting travel between Canada and the US even though Canada has confirmed more than nine times the number of coronavirus cases reported in Mexico. Canada has 109 confirmed cases and one related death.

The closure of the US-Mexico border to southbound traffic during a crisis was portrayed in the 2004 movie, The Day After Tomorrow, where a massive storm creates freezing temperatures in the northern parts of the United States, and Americans flee to Mexico to survive. In the movie, as Americans overrun the border, Mexico at first blocks the border, but then agrees to accept Americans as refugees.

At the end of the movie, the US President if forced to shelter in a camp in Mexico City, and thanks Mexico for its help in savings Americans.