U.S. President Barack Obama has said he will keep his election campaign promise to have all of his country''s combat troops home from Iraq by the end of this August.

"As a candidate, I promised that I would end this war, and that is what I am doing as president," Obama said in a State of the Union address to a joint session of Congress. "Make no mistake: this war is ending, and all of our troops are coming home."

He said that all U.S. combat troops would leave Iraq by August 31, 2010, and that the 35,000-50,000 non-combat troops to remain would leave by December 31, 2011, as per the terms of a deal between the Iraqi government and the Bush administration.

On Afghanistan, Obama said while there were "difficult days ahead", the U.S. was "increasing our troops and training Afghan Security Forces so they can begin to take the lead in July of 2011, and our troops can begin to come home."

Obama was speaking ahead of a London conference on Afghanistan on Thursday. The 60-nation meeting will be dominated by talks on possible negotiations with the radical Islamic Taliban movement in a bid to bring stability to the war-ravaged Central Asian state.

The president had strong words for Iran, telling the Islamic Republic''s leaders that they would face "growing consequences" over their refusal to fulfill their "obligations" on the country''s disputed nuclear program.

On North Korea, which on Thursday fired several artillery shells in the direction of South Korea, Obama said the communist state "now faces increased isolation and stronger sanctions - sanctions that are being vigorously enforced."