President Donald Trump says the United States will send 1,000 more service members to Poland as he announces a broadening security and economic alliance.

Trump is discussing the additional troops as part of a White House press conference with visiting Polish President Andrzej Duda. Before the two men spoke, a single F-35 flew over the White House to emphasize Poland's plan to purchase the aircraft.

Trump says the Polish government will pay for the infrastructure to support the additional troops. He is also praising Poland for increased defense spending to meeting its NATO commitments.

Trump says the two countries have agreed to increased sales of liquefied natural gas to Poland to demonstrate growing economic cooperation between the two countries.

Trump also said that he is "looking very seriously at going back to Poland" and is thinking about doing so "sometime in September."

That month will mark the 80th anniversary of the start of World War II, when Nazi Germany and then the Soviet Union invaded Poland.

Trump last visited Poland in July, 2017, when he delivered a speech in which he vowed to confront "new forms of aggression" targeting the West and received an enthusiastic reception from a crowd of thousands chanting his name.

(The Associated Press contributed to this report.)