Spain says it and other European countries were told that the NSA whistleblower Edward Snowden was on board the Bolivian presidential plane that was diverted to Austria this week, causing a diplomatic row.

The foreign minister, José Manuel García-Margallo, said on Spanish National Television on Friday that "they told us that the information was clear, that he was inside".

The minister did not say who supplied the information and declined to say whether he had been in contact with the United States. But he said European countries' reactions were based on this information.

The Bolivian president, Evo Morales, claims the US pressured European countries to deny the plane flyover permission on Tuesday on suspicion that Snowden was using the flight as part of his bid to seek asylum.

Morales has warned he might close the US embassy in his country over the forced landing, which he called a violation of international law. He had been returning from a summit in Russia during which he had suggested he would be willing to consider a request from Snowden for asylum.

"We met with the leaders of my party and they asked us for several measures and if necessary, we will close the embassy of the United States," Morales said on Thursday. "We do not need the embassy of the United States."

Morales made his announcement as the leaders of Venezuela, Ecuador, Argentina and Uruguay joined him in Cochabamba, Bolivia, for a special meeting to address the diplomatic row. At the end of the summit a statement was issued demanding answers from France, Portugal, Italy and Spain. The US was not mentioned in the statement.

Morales has said that while the plane was parked in Vienna, the Spanish ambassador to Austria arrived with two embassy personnel and they asked to search the plane. He said he denied them permission.

García-Margallo said on Thursday that Spain did not bar Morales from landing in its territory.

France sent an apology to the Bolivian government. But Morales said "apologies are not enough because the stance is that international treaties must be respected".

Morales said he never saw Snowden when he was in Russia, and Bolivia had not received a formal request from him for asylum.

Despite the complaints, there were no signs that Latin American leaders were moving to bring Snowden to the region that had been seen as the most likely to grant him asylum.