Washington on Thursday began requiring visas for Europeans and Asians who had traveled to certain Middle Eastern and African countries seen as hotspots for extremism.

That law was passed by the Republican Party-dominated Congress in the wake of the deadly Paris attacks.

The US State Department also said it's required by law to revoke travel authorizations held by citizens normally allowed without a visa if they are also dual Iranian, Iraqi, Sudanese or Syrian citizens.

That's led to criticism from some lawmakers.

Sen. Dick Durbin, a top Democrat, complained Thursday that "singling people out because of their national origin is fundamentally at odds with American values and invites discrimination against American citizens who are dual nationals."

However, the administration of US President Barack Obama has outlined exceptions. People who could be eligible for a waiver if their travel was on behalf of international organizations or humanitarian groups, or journalists who carried out reporting in the four countries.

Partisan fight over enforcement

Republican lawmakers, who championed the new rule, complained that the president was watering down the law.

"The Obama administration is blatantly breaking the law, a law the president himself signed," said House Homeland Security Committee Chairman Michael McCaul. "This is not a difference of opinion over statutory interpretation; it is a clear contradiction of the law and the agreement we reached with the White House. President Obama is again putting his relationship with Iran's supreme leader over the security of Americans."

Despite different interpretations of the law, many Europeans and citizens of Asian countries such as Singapore, South Korea and Japan who have visited Syria, Iran, Iraq or Sudan since 2011 will be required to apply for visas in advance of any travel to the US.

An estimated 20 million people, or about 40 percent of all international visitors, enter the United States without a visa for business or pleasure for up to 90 days.

The fine print

Citizens affected by the new rule are nationals from: Andorra, Australia, Austria, Belgium, Brunei, Chile, the Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Japan, Latvia, Liechtenstein, Lithuania, Luxembourg, Malta, Monaco, the Netherlands, New Zealand, Norway, Portugal, San Marino, Singapore, Slovakia, Slovenia, South Korea, Spain, Sweden, Switzerland, Taiwan and the United Kingdom.

jar/bw (AP, Reuters)