+THE UNITED STATES Internal  Revenue Service (IRS) has opened a file  on  the ‘Panama Papers’ revelations of  millions of files of  Panama law firm  Mossack Fonseca and has urged US citizens whose names appear to come  forward to “clarify” their situation before investigations move further.

Meanwhile  Preet Bharara, Attorney for the Southern District of New York representing the US Department of Justice  has opened a criminal investigation

"While we cannot make statements on specific cases, we take very seriously these kind of accusations and investigate all tracks in our power to confirm these allegations," an IRS representative told La Prensa.

"What we can announce is that without giving details on specific cases, we will begin to verify the evidence we obtain through national sources and countries with which we have agreements," the official added.

The research led by ICIJ have shown alleged systematic practice of Mossack Fonseca for allegedly helping clients avoid paying taxes. The IRS representative said that publications that have appeared in media in the world will serve as part of the tracks for diligence.

"The IRS obtains information through a variety of sources, and if we find that there was a criminal activity, we will take action to confirm the allegations. We always need documents to validate suspicions, and our challenge has always been getting those documents, "the official said.

The work could be shared with tax offices in other countries, the official said. "We work all the time with other countries, demonstrating why we have offices in Panama and elsewhere. Part of our job is to facilitate the exchange of information internationally."

Following international publication on the activities of the Panamanian firm President Barack Obama said: "Evading taxes is a global problem. Not something focused in another country, because there are US citizens who take advantage of these benefits, "said the president.

Obama's statement is on the same line of the warning made by the IRS in the United States a few days ago, according to NBC.

Senior  directors of the institution urged US citizens mentioned in the investigation to clarify the situation before they "read" documents.

"People who hide assets offshore must fall within the tax progress internationally. More than ever, the best option is to step out voluntarily, "said the institution.