BOGOTA, Colombia (AP) — Colombia’s president says that Venezuelan migrants who are living in the country without residence permits won't be given free COVID-19 vaccines when those arrive in the South American country — possibly leaving hundreds of thousands unvaccinated.

In an interview Monday with Blu Radio, President Ivan Duque said that giving free vaccines to undocumented immigrants could “unleash a stampede” of Venezuelans crossing into neighboring Colombia to get vaccinated.

“Our priority will always be Colombian citizens” Duque said, though he added that migrants who have regularized their status in Colombia would also be eligible for free vaccines as long as they fall into the categories that the Ministry of Health has outlined for who gets vaccinated first.

More than 1.8 million Venezuelans currently live in Colombia and about 60% of them do not have a residence permit, according to Colombian immigration authorities.

Duque’s comments were widely rejected by health experts and migrants’ rights groups, who said that leaving out a vulnerable group from a vaccination program would be counterproductive and unethical.

“It’s important to protect everyone from COVID-19 without distinction” said Dr. Juan Carlos Viloria, who leads an association of Venezuelan immigrants in Colombia. “If you don’t, you put thousands of people at risk, including those in host communities and those who are migrating.”

Viloria said that international donors could help Colombia and other countries in the region to obtain vaccines for Venezuelan migrants.

During the first months of the pandemic, more than 100,000 Venezuelans living in Colombia returned home after losing their jobs. But as Venezuela’s economic crisis has continued to deepen and the minimum wage has fallen to less than $1 a month, thousands have returned to Colombia and other South American countries in search of work.

Many sleep in shelters and make long treks across the country on foot and on the back of trucks until they reach their destinations.

That makes them more likely to catch the virus.

Colombia has registered more than 1.5 million cases of COVID-19 so far, and health authorities have said that they will start to implement a national vaccination program in February. The nation of 50 million people has already bought vaccines from Pfizer and is in talks with other companies to acquire more.

Colombia’s government says it aims to vaccinate 35 million people next year, starting with health workers, senior citizens and people with diseases that make them more vulnerable to the virus.