BRASILIA, Dec. 18 -- Brazilian President Dilma Rousseff said Wednesday she "reserved the right not to comment" on an appeal for political asylum by former U.S. National Security Agency (NSA) contractor Edward Snowden.

In a meeting with reporters at the presidential palace in the capital Brasilia, Rousseff said Snowden has not officially requested asylum and it was not up to her to "interpret letters."

"I fully reserve the right not to comment on something that has not been sent. And more than that, I don't interpret letters, that 's not my job," said Rousseff.

"Nothing was sent to us, how am I going to comment?" asked Rousseff.

Snowden addressed an open letter to "the people of Brazil" Tuesday, indicating he would welcome permanent asylum in Brazil.

In his letter published in Brazilian daily Folha de Sao Paulo, Snowden did not directly ask for asylum, but offered to help Brazil investigate the extent of NSA spying on the South American country, and said he needed the security of permanent asylum to do so.

Brazil's Foreign Ministry confirmed it has not received a formal asylum request, and thus cannot comment on the matter.

In conjunction with the publication of the letter, Snowden's supporters have organized an online drive to gather signatures to pressure Rousseff into giving him asylum.

After fleeing the U.S. and landing at Moscow's airport in July, the former intelligence worker who blew the whistle on the NSA's global spying was granted temporary asylum by Russia.