A reporter's laptop shows the Wikipedia blacked out opening page in Brussels in this file photo dated January 18, 2012. REUTERS/Yves Herman

ANKARA (Reuters) - Online encyclopedia Wikipedia has appealed to Turkey’s constitutional court against a government decision to block access to its website, broadcaster CNN Turk said on Tuesday, a case that has heightened concerns about censorship in Turkey.

Turkey’s telecommunications watchdog said two weeks ago that access to Wikipedia had been blocked, citing a law allowing it to ban access to websites deemed a threat to national security.

The block on the site was prompted by two Wikipedia entries accusing Turkey of links to Islamist militant groups, local media have reported. The communications ministry has said Wikipedia was attempting to run a “smear campaign” against the country, saying some articles purported that Ankara was coordinating with militant groups.

A Turkish court on Friday rejected an appeal by the Wikimedia Foundation, which operates Wikipedia, against the blocking, saying that while freedom of speech was a fundamental right, it can be limited in cases where there is a “necessity for regulation”.

The Wikimedia Foundation has called for the Turkish government to restore full access to the site.