U.S. Defense Secretary Robert Gates said the United States has not pressured Turkey to take part in a NATO missile defense system, but expressed hope Ankara would endorse plans for the anti-missile shield.

Gates said U.S. and Turkish officials have discussed the possibility of Turkey actively participating in the proposed missile defense system directed against Iran.

"The US has engaged Turkey in political and military dialogue on its potential technical and operational contributions should NATO adopt this approach," Gates said in a speech to the American-Turkish Council in Washington. "Contrary to some press reports, we are not pressuring Turkey to make a contribution," said Gates, according to a text of the speech released by the Pentagon, AFP reported.