BRUSSELS -- The European Union's executive body was accused Thursday of failing to properly check the business interests of its top officials after leaked documents showed its former competition chief was a director of an offshore company based in the Bahamas.

Critics pounced on the revelation that Neelie Kroes, who led the European Commission's powerful anti-trust unit between 2004 and 2010 and is now a paid adviser to Uber and Bank of America, had an undisclosed interest in a company in the Bahamas as further evidence of the EU Commission's lax approach to vetting.

As a result, European Commission President Jean-Claude Juncker is facing calls to tighten up the rules on potential conflicts of interest. Juncker was already under pressure to do so following the news this summer that his predecessor, Jose Manuel Barroso, had taken a top job at investment bank Goldman Sachs.

Kroes' name was one of the most high-profile to emerge in a cache of documents of the Bahamas' corporate registry that was leaked Wednesday by the International Consortium of Investigative Journalists and media partners.

The leak revealed the names of directors and owners of more than 175,000 Bahamian companies, trusts and foundations, ranging from prime ministers and princes to convicted felons.

The disclosures follow the international uproar over the leak of the so-called "Panama Papers" earlier this year that revealed details on offshore accounts that helped foreigners shelter their wealth. Like Panama, the Bahamas, a chain of 700 islands in the Atlantic Ocean, is a renowned tax haven.

Anti-corruption watchdog Transparency International said the Commission's verification procedures are simply not good enough.

"It is incredible that something like this -- which is a clear breach of the rules and could have led to a major conflict of interest -- was undetected by the European Commission for so many years," Transparency's EU director Carl Dolan told The Associated Press.

"The European Commission carries out very limited checks or verifications on the self-declarations of Commissioners when they come into office."

The Commission argued it had been powerless to make Kroes disclose all of her business interests.

"There are certain things that even the strictest rules can't fix," chief EU Commission spokesman Margaritis Schinas told reporters. In the future, he said the Commission "will make sure that memory doesn't fail here when it comes to declarations of interest." He did not explain how it would do so.

Kroes was revealed as director of one company -- Mint Holdings -- that she had not declared when she became the EU Commissioner for Competition in 2004. Mint Holdings had been allegedly set up from the United Arab Emirates, with the aim of raising money to buy some assets from energy giant Enron, which subsequently collapsed following an accounting scandal.

Kroes, who in 2010 moved on to become the Commissioner responsible for digital matters until 2014, said through a lawyer that she did not declare her role because the company never became operational, according to the ICIJ. She did, however, declare other business interests.

Kroes informed the Commission about the facts last Friday in an email.

Juncker has written to her seeking more details. The Commission could also examine decisions she took during her term in office to identify whether there may have been any conflict of interests.

If she is found to have breached EU laws, Kroes could face court action, which might lead to her losing her generous Commission pension or other benefits.

The revelations surrounding Kroes come in the wake of the controversy surrounding former Commission President Barroso, who joined Goldman Sachs after his tenure at the Commission ended. His move was criticized by those who see it as an inappropriate use of his experience in public service.

Goldman Sachs has a bad image in some parts of Europe as it is alleged to have helped the Greek government hide details about its national debt for over a decade.

"Barroso has already undermined the image and the credibility of the Commission by announcing that he will work for Goldman Sachs, the bank which helped Greece to conceal its public accounts," said Gianni Pittella, president of Socialist and Democrats group in the European Parliament.

Other lawmakers said the latest revelations surrounding Kroes symbolize a wider malaise gripping the EU.

"The European Commission too often means European Corruption. It is this European Union of big business and ruthless theft of Brussels oligarchs which people disdain. The very same politicians that preach to our people to cut back on wages, pensions and public services join shady criminals in the trillion euro industry of tax dodging, money laundering and corruption," said left-wing German lawmaker, Fabio De Masi.

Britain's interior minister, Amber Rudd, is also reported to have been named in the files as being a director of two offshore companies. Before entering Parliament in 2010, Rudd had had a wide-ranging career in business.

A spokesperson for Rudd played down the significance of the leak: "It is a matter of public record that Amber had a career in business before entering politics."

Pylas contributed from London. Helena Alves in Brussels contributed to this report