U.S. President Barack Obama met his Turkish counterpart Recep Tayyip Erdogan in Washington, the White House said, amid serious tensions over press freedom and the war in Syria, AFP said.

Having previously stated the pair were unlikely to hold sit-down talks -- a decision widely perceived as a snub by Washington -- the White House said the two men had in fact met on the margins of a nuclear security summit.

They discussed "U.S.-Turkey cooperation on regional security, counterterrorism, and migration," it said.

The White House has been increasingly outspoken in recent months about threats to free speech and democracy in Turkey, AFP says.

And on Thursday, March 31 it restated its belief in the need for press freedom in Turkey, amid ugly scenes at an Erdogan speech in the U.S. capital.

Ahead of Erdogan's arrival at the Brookings Institute, Turkish security officials clashed with protestors -- both sides exchanging insults and scuffling -- before police were able to separate them.

The Turkish guards also set about the press. One aimed a chest-high kick at an American reporter attempting to film the harassment of a Turkish opposition reporter while another called a female foreign policy scholar a "whore."