BEIJING -- More illegal spying activities conducted by the US National Security Agency (NSA) have been leaked to the world after former intelligence contractor Edward Snowden first blew the whistle in June.

Newly-revealed victims include presidents of Mexico and Brazil, France's Foreign Ministry and diplomats, as well as the UN headquarters in New York.

Mexican President Enrique Pena Nieto's emails were read, according to a document dated June 2012 disclosed by Guardian reporter Glenn Greenwald, who obtained secret documents from Snowden.

As for the Brazilian leader, the NSA tracked the communications between President Dilma Rousseff's aides and their contacts with third parties, Greenwald told Globo TV's news program "Fantastico."

Brazil's O Globo newspaper reported last month that Brazil is the top target in Latin America for the NSA's intelligence gathering effort.

Even though US Secretary of State John Kerry defended the program as lawful measures that helped foil terror attacks, Brazil was not satisfied with the explanations and stood ready to bring the case to international organizations, probably the United Nations.

The report said the NSA collected the data through an undefined association between US and Brazilian telecommunications companies.

German magazine Der Spiegel said Sunday that the NSA also spied on France's Foreign Ministry and diplomats and the Qatar-based TV channel  Al-Jazeera.

Der Spiegel reported that the NSA monitored the internal computer network of the ministry by accessing so-called virtual private networks (VPN).

The NSA was "interested in (France's) foreign policy objectives, especially the weapons trade, and economic stability," the magazine said.

Al-Jazeera was another NSA target as the channel had broadcast audio and video messages from al-Qaida leaders for years, according to a March 2006 NSA document seen by Der Spiegel.

In late August, the German magazine disclosed that the NSA had bugged the UN headquarters in New York.

In the summer of 2012, NSA succeeded in getting into the UN video conferencing system and cracking its coding system, according to Der Spiegel.

Besides, the European Union and the International Atomic Energy Agency (IAEA) were among those institutions that were targeted by US spying program, it reported.

The leaks, one round after another, have embarrassed the United States by exposing how massive the extent of its intelligence collecting program goes and how grossly that the rights of other countries and citizens were violated.

The US intelligence surveillance program code-named PRISM is said to give the NSA and FBI access to the systems of nine of the world's top Internet companies, including Google, Facebook, Microsoft, Apple, Yahoo and Skype.