(CNN) -- Venezuelan President Hugo Chavez and U.S. Secretary of State Hillary Clinton shook hands on the sidelines of Brazil's presidential inauguration this weekend, state media reported.

The Venezuelan state-run AVN news agency said the two discussed specific issues in a brief, informal conversation. Both leaders were in Brazil for the inauguration of Dilma Rousseff, the country's first female president.

"We greeted each other. (Clinton), I think, was entering the room. She had a very spontaneous smile and I greeted her with the same effusiveness. ... It was a pleasant moment. We spoke about two or three specific things," Chavez told state-run VTV.

State media did not specify what issues were discussed. As of early Sunday morning, the U.S. State Department had not released any details about the conversation.

Diplomatic relations between the two countries have been particularly strained recently.

Last week the State Department announced that the U.S. government had revoked the visa of the Venezuelan ambassador to Washington. That move came in response to Venezuela's decision not to accept the diplomatic credentials of Larry Palmer, the U.S. ambassadorial nominee for the South American country, State Department spokesman Mark Toner said.

Earlier, Toner told reporters that diplomatic relations with Venezuela were in the "national interest."

"We believe it's in our national interest to have an ambassador in Caracas so that we can candidly express our views and engage with the government of Venezuela. ... There are tensions in the relationship, and it's precisely because of that that we feel that it's important to have appropriate diplomatic relations," he said.

Venezuela's government has said it considers statements Palmer made about the country "unacceptable declarations."

In response to a questionnaire by Sen. Richard Lugar, R-Indiana, Palmer said last year that he had concerns about freedom of expression in Venezuela and that there are "clear ties" between the Venezuelan government and Colombian guerrillas.

Venezuela "considers that the content of those statements sets a precedent of meddling and interventionism from someone that has not even arrived in Venezuelan territory yet," the Venezuelan government said in a statement last year.