BRUSSELS (Reuters) - U.S. Secretary of State Rex Tillerson, in his first NATO meeting in Brussels, told allies that the United States will uphold previous agreements and ensure the alliance has the capability to defend itself, including from Russian aggression. He also pressed allies to meet a defense spending goal of 2 percent of gross domestic product, urging each country to either meet or have a plan in place to fulfill funding commitments to NATO by a May summit of NATO leaders. 