A series of documents published by WikiLeaks has shown that the U.S. National Security Agency allegedly spied on world leaders and bugged their various meetings. Among the leaders spied on by the NSA were U.N. Secretary-General Ban Ki-moon, German Chancellor Angela Merkel, former Italian Prime Minister Silvio Berlusconi and Prime Minister Benjamin Netanyahu. WikiLeaks said that the documents were classified as top-secret, the highest security classification of any documents leaked thus far. According to the documents, the U.S. bugged a 2010 meeting between Netanyahu and Berlusconi. A WikiLeaks summary of the meeting said that Netanyahu had "begged" Berlusconi for help in dealing with U.S. President Barack Obama, but it is unsure whether that is an accurate characterization of what was said in the meeting. Netanyahu met with Berlusconi after Israel announced it would build 1,600 housing units in the Jerusalem neighborhood of Ramat Shlomo. According to the summary of the meeting, Netanyahu asked Berlusconi for help in mending U.S.-Israeli ties, which have been fraught under the Obama administration. Netanyahu said that the decision on the housing construction had been consistent with decades-long Israeli policy. Berlusconi reportedly put Italy at Israel's disposal in the latter's attempts to warm up frosty relations with Washington. The documents go on to reveal that a meeting between Merkel and Ban on global warming had also been bugged. WikiLeaks alleges that the U.S. government used information from the meeting to protect the big oil companies. WikiLeaks founder Julian Assange said, "Today we showed that U.N. Secretary-General Ban Ki-moon's private meetings over how to save the planet from climate change were bugged by a country intent on protecting its largest oil companies. "We previously published [former U.S. Secretary of State] Hillary Clinton orders that U.S. diplomats were to steal the secretary-general's DNA. The U.S. government has signed agreements with the U.N. that it will not engage in such conduct against the U.N.-- let alone its secretary-general. "It will be interesting to see the U.N.'s reaction, because if the secretary-general can be targeted without consequence, then everyone from world leader to street sweeper is at risk," Assange said. Earlier this month, a U.N. human rights expert called on Sweden and Britain to follow the recommendation by a U.N. panel to allow freedom of movement for Assange. Alfred-Maurice de Zayas said the countries should set a "good example" and follow the finding announced Feb. 5 by the U.N. Working Group on Arbitrary Detention that Assange should be free to leave the Ecuadorean Embassy in London. Authorities in Britain and Sweden rejected the finding, saying Assange has detained himself by seeking refuge in the Ecuadorean Embassy in London after facing allegations of sexual misconduct in Sweden. They insisted he would be arrested if he left.