The U.S. is taking steps to better identify who is allowed into the country.
After much back and forth on Capitol Hill, Congress has come to an agreement on tightening security around the visa waiver program.
The changes are a direct result of the Paris attacks.
Click here for our full coverage of the attacks in Paris.
Some of the assailants were citizens of European countries with ties to terrorism.
Right now 20 million people enter the U.S. every year through the visa waiver program.
Citizens of 38 countries, including most of Europe, are able to visit the U.S. without the security screenings required for a traditional visa.
That’s until now.
Tuesday Senator Chris Murphy, a member of the Foreign Relations Committee, explained the changes passed as part of the federal budget two weeks ago.
"The visa waiver program is a huge security gap for the United States that we have now begun to close with legislation passed by Congress,” said Murphy.
From now on everyone participating in the visa waiver program will have an electronic chip in their passport.
This will allow the U.S. to track individuals as they move through Europe and the United States.
It also requires participating countries increase their information sharing with U.S. law enforcement.
"For instance, we now are going to require every country to report a lost or stolen passport within 24 hours to the United States if those countries want to be part of the visa waiver program,” said Murphy.
Additionally, any citizen of participating countries who have traveled to Iraq, Syria, Iran, or Sudan are ineligible for it now.
"It doesn't mean that a European citizen that's traveled to Syria won't be able to come to the United States,” said Murphy, “It simply means that they would have to apply for a visa in order to do that, which would require a much higher level of security screening."
Murphy doesn't think it's perfect but says it is a compromise between Republicans and Democrats.
The President signed it into law on December 18.