President Donald Trump’s new ban and restrictions on travel to the U.S., affecting a total of 19 countries, took effect on Monday.

The new regulations include a total ban on the entry of Haitian nationals and restrict the travel of Cuban and Venezuelan nationals in the interest of national security, according to the White House.

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South Florida is home to the largest Cuban and Haitian diaspora communities in the world, and the largest Venezuelan community in the U.S.

The travel ban and restrictions have left several local residents asking how it’ll work and who is impacted.

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In a nut shell: there are lots of ways you can be granted entry into the U.S., including as a tourist, a student, immigrant and more. The ban means nationals from the 12 listed countries, including Haiti, can’t come in at all (barring a few exceptions). The restrictions on the other seven countries, including Cuba and Venezuela, suspend entry on some visas, but not all.

Here’s what you need to know.

Who exactly is banned from traveling to the U.S.?

Trump has fully banned the entry of nationals from 12 countries to the United States. They are: Afghanistan, Burma, Chad, Republic of the Congo, Equatorial Guinea, Eritrea, Haiti, Iran, Libya, Somalia, Sudan and Yemen.

The entry of nationals from seven other countries are also restricted. They are: Burundi, Cuba, Laos, Sierra Leone, Togo, Turkmenistan and Venezuela.

What is the difference between a ban and restriction?

Nationals of the countries included in the ban, such as Haiti, cannot come into the U.S. as either immigrants or nonimmigrants (a tourist, for example).

Foreign nationals of the countries under travel restrictions cannot come into the U.S. as immigrants, and some nonimmigrant visas are suspended.

How does this affect the travel of Haitians, Cubans and Venezuelans into the U.S.?

Haitian nationals cannot come into the U.S. at all, barring a few exceptions.

Cuban and Venezuelan nationals cannot come into the U.S. as immigrants, and their nonimmigrant visas are restricted.

Specifically, the entry of Cuban and Venezuelan nationals into the U.S. as nonimmigrants on B-1, B‑2, B-1/B-2, F, M, and J visas, is suspended. These are visas issued for reasons including business, tourism, schooling and exchange programs, respectively.

Consular officers have additionally been instructed to “reduce the validity for any other nonimmigrant visa issued to nationals of Cuba or Venezuela to the extent permitted by law,” according to the White House.

Are there exceptions to the travel ban? Who is exempt?

Yes. The ban will not apply to U.S. citizens, lawful permanent residents or existing visa holders.

“In other words, the proclamation will not apply to nationals from the list of banned countries who have green cards or who are living in the United States with visas,” NBC News reports. “It will also not affect nationals of the banned countries who have citizenship in second countries and are entering the United States with passports from unrestricted countries.”

Other exemptions include immediate family immigrant visas, Afghans who helped the U.S. government during the war in Afghanistan, ethnic and religious minorities facing persecution in Iran, athletes from banned countries who are entering the United States for the World Cup or the Olympics and children who are being adopted.

Can I go to Haiti, Venezuela, Cuba or any other of the 19 countries included in the travel ban and restrictions and come back?

The ban affects travel into the U.S., not travel out.

So if you are a U.S. citizen, lawful permanent resident or existing visa holder, assuming that any of the 19 countries allow your entry, you may go and come back to the U.S.

However, immigration attorney Rosaly Chaviano told our sister station Telemundo 51 in Spanish that she would urge caution.

“I would not advise nationals of these countries to travel [out of the U.S.], especially in the beginning, to avoid confusion both with the airlines and officials,” she said.

What is the reason for the travel ban and restrictions?

The White House says the 12 countries, including Haiti, affected by the ban were “found to be deficient with regards to screening and vetting and determined to pose a very high risk to the United States.”

Travel is restricted from the other seven countries, including Cuba and Venezuela, because they “also pose a high level of risk to the United States” for various reasons.

In a YouTube video, the president also cited a recent antisemitic attack involving a “makeshift flamethrower” that left 12 people hurt in Boulder, Colorado, allegedly perpetrated by an Egyptian national, as justification for the ban.

“The recent terror attack in Boulder, Colorado, has underscored the extreme dangers posed to our country by the entry of foreign nationals who are not properly vetted as well as those who come here as temporary visitors and overstay their visas,” he said in the video. “We don’t want them.”

Egypt is not included in the travel ban or restrictions.

On the campaign trail, Trump had also promised to bring back the ban he implemented in his first term, which applied to six Muslim-majority countries.

Why is travel banned from Haiti?

The White House cites U.S. Department of Homeland Security’s Overstay Reports frequently throughout the proclamation.

According to these reports, “Haiti had a B1/B2 visa overstay rate of 31.38 percent and an F, M, and J visa overstay rate of 25.05 percent. Additionally, hundreds of thousands of illegal Haitian aliens flooded into the United States during the Biden Administration. This influx harms American communities by creating acute risks of increased overstay rates, establishment of criminal networks, and other national security threats. As is widely known, Haiti lacks a central authority with sufficient availability and dissemination of law enforcement information necessary to ensure its nationals do not undermine the national security of the United States.”

Why is travel restricted from Cuba?

“Cuba is a state sponsor of terrorism,” the proclamation reads. “The Government of Cuba does not cooperate or share sufficient law enforcement information with the United States. Cuba has historically refused to accept back its removable nationals. According to the Overstay Report, Cuba had a B-1/B-2 visa overstay rate of 7.69 percent and an F, M, and J visa overstay rate of 18.75 percent.”

Why is travel restricted from Venezuela?

The proclamation says that “Venezuela lacks a competent or cooperative central authority for issuing passports or civil documents and it does not have appropriate screening and vetting measures. Venezuela has historically refused to accept back its removable nationals. According to the Overstay Report, Venezuela had a B‑1/B-2 visa overstay rate of 9.83 percent.”