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Dual citizens from Iraq, Iran, Syria and Sudan are protesting against a new US programme that restricts their travel.

Neysun Rouhani and his wife live in the UK. He's a concert pianist and piano teacher who travels to the US often, both for work and to visit family.

But once changes to the US visa waiver programme are implemented in 2016, he will be required to apply for a visa with an in-person interview at the US embassy in London.

"It makes my life more difficult. Right now I'm not sure the trip we have planned since five months ago will happen or not in January," he says.

The US Congress has passed a measure as part of a budget bill that will no longer allow citizens of 38 countries - including the UK - who have either travelled to Iraq, Syria, Iran or Sudan in the past five years or are dual nationals of these states, to travel to the US without a visa.

The president signed the bill into law on Friday.

Rouhani, a dual citizen of the UK and Iran, will be affected. As a British citizen he could be eligible for a 10-year, multiple-entry visas for business and tourism - but not to perform. That, as before, requires a separate permit.

Image copyright Laura Radford Image caption Neysun Rouhani

The move has angered European diplomats.

"If you're a terrorist, you don't have a great big Syria stamp in your passport - you have Turkey, for example. It's not going to catch the people who don't travel legitimately, it's going to target the people who do travel legitimately," an EU official told the BBC.

All European Union ambassadors of member states recently published an editorial arguing against the changes - an unprecedented occasion to see a unanimous agreement among all the representatives of the union, the official said.

The new legislation comes on the heels of the terrorist attacks in Paris last month that sparked fears of a similar act being carried out on American soil. This prompted lawmakers to take a look at tightening the borders, igniting national debate about refugees.

"If a terrorist has been to Iraq and Syria and wants to get to the US, they will likely go through Europe. That's the problem," said one congressional aide to the BBC. "Europe doesn't have a threat of foreign fighters coming from our country."

The legislation gained even more support after December 2, when a radicalised married couple - Tafsheen Malik and Syed Rizwan Farook - killed 14 and wounded 22 in San Bernardino, California.

Farook was a US citizen raised by Pakistani immigrant parents. He travelled to Saudi Arabia to meet his future wife, Malik, who grew up in Pakistan, in 2013. She was granted a K1 fiancee visa by the US Embassy in Pakistan after clearing a background check.

Though neither of the killers was a dual citizen, the attack led to renewed fears about the visa process. Modifications to the visa waiver bill in the House were added at the last minute to include not just people who had travelled to Iraq and Syria but also dual citizens and people who had visited countries that are US-designated state sponsors of terrorism - including Sudan and Iran.

Image copyright Getty Images Image caption Syed Farook (left) and Tashfeen Malik (right) killed 14 in California, leading to concerns about the US visa process

Iranians living in the US say they are outraged that Iran is included on the list of barred countries, but countries where the San Bernardino attackers were born or travelled to are not.

"If the intent truly is to protect America from Isis and not target Iran and the nuclear deal, then why is Iran included but travel to Saudi Arabia and Pakistan is not? This makes no sense," says Trita Parsi of the National Iranian American Council, who has been leading the effort on Capitol Hill to fight this change.

Should the EU invoke reciprocity when their policy is reviewed in the spring, this could mean the same requirements for Iranian-Americans hoping to visit their families abroad.

Critics say the new rule will keep families apart.

"This legislation was ill conceived and targets ordinary people," says Navid Sadoughi, one of the members of a Facebook group meant to spread awareness and rally against the bill. The page gained 70,000 members in its first three days.

A swath of this Iranian diaspora includes people who have citizenship to Iran but have not returned since the Islamic Revolution. Many say the process of actually renouncing citizenship and giving up a passport is quite complicated.

It is unclear how the new visa waiver programme changes will be implemented, a process which is led by the US Department of Homeland Security.

"We'll look at how the administration is going to implement this. There's always a bit of leeway, room for common sense," says one EU official.

But for those with dual passports, the message is discouraging. Amirali Pour Deihimi, an Australian architect who works on sustainable design, says the rule could keep him from attending conferences and seminars in the US.

"With global warming, we need to bring the world together, not separate it," he says.

He's visited the US in the past, but says he can't see making the effort in the future.