Authorities in London have arrested WikiLeaks founder Julian Assange on an arrest warrant issued by Sweden.
Assange is wanted for questioning in Sweden about allegations of rape, sexual molestation and unlawful coercion. He denies the claims.
The WikiLeaks founder is due to appear in a London court later Tuesday.
Assange's lawyers have said he will fight extradition to Sweden, for fear he could be turned over to the United States.
Assange founded the WikiLeaks website that has released some 250,000 secret U.S. diplomatic cables over the Internet.
A spokesman for the website says the arrest of Assange does not affect plans for the release of more documents.
Prior to his arrest Tuesday, WikiLeaks leaked diplomatic memos that say NATO drew up military plans to defend Baltic nations against a Russian attack after Russia's conflict with Georgia in 2008. The Guardian newspaper says the memos reveal that secret plans to protect Estonia, Latvia and Lithuania were drawn up at NATO headquarters at the urging of the United States and Germany.
The WikiLeaks cables point to underlying tensions in the relationship between the former Cold War adversaries.
Earlier, WikiLeaks released what it said was a secret U.S. government list of infrastructure and resource sites around the world that the United States considers critical to its interests.
U.S. and British officials said the publication of the list puts lives at risk.
The leaked list of U.S. critical interests, which appears in U.S. diplomatic cables dating from 2008, includes the ********s of vaccine manufacturers across Europe, undersea cables, ports, and key mineral and power resources from Asia to Brazil.
U.S. Secretary of State Hillary Clinton Monday described the release of the cables as "illegal," saying it poses real concerns and even potential damage to the United States' friends and partners around the world. Clinton said this theft of U.S. government information and its publication without regard to consequences are deeply distressing.
U.S. Attorney General Eric Holder condemned the release Monday "in the strongest terms" and said the national security of the United States has been put at risk. Holder also said an active criminal investigation remains under way.