WASHINGTON — President Obama warned yesterday "there will be difficult days ahead" in Iraq and said the U.S. will remain a strong partner to Iraq for its security.

Obama, speaking to military families invited to the White House for Independence Day festivities, praised Iraq's independence and thanked troops for their service. Because of the courage, capability and commitment of soldiers who have served in Iraq, the country is now "taking control of its own destiny," he said.

The White House invited hundreds of military families to attend the Fourth of July gathering on the White House South Lawn. The celebration included volleyball and face-painting and refreshments such as hot dogs, hamburgers, potato salad, corn on the cob, ice cream and lemonade.

Obama daughters Sasha and Malia joined their parents as the president addressed the military families. Malia Obama turned 11 yesterday.

"I should say that there's also one girl in particular who's just thrilled that all of you are here — and that is Malia Obama, because this happens to be her birthday, as well," Obama said, drawing applause. "When she was younger, I used to say that all these fireworks were for her. I'm not sure she still buys that."