The statement followed talks in which the two leaders discussed the downing last week of an Malaysia Air jetliner by Russian backed rebels in Ukraine.
"This afternoon, President Obama spoke with Polish President Komorowski to discuss the situation in Ukraine and the upcoming NATO Summit in Wales," the statement said.
"President Obama and President Komorowski agreed on the importance of raising defense spending among European members of NATO, as well as on the importance of alliance-wide and credible contributions to NATO's reassurance efforts in Central and Eastern Europe," it continued.
The White House statement came a day before today's meeting in Warsaw of the leaders of nine NATO members from Central and Eastern Europe.