UNITED NATIONS—The U.N. called on any nation with information that may shed light on the 1961 death of Secretary-General Dag Hammarskjöld to disclose it after evidence emerged in the past few years suggesting foul play.

The request was part of a resolution adopted by all 193 nations in the U.N. General Assembly on Monday, which also establishes an independent panel of experts to examine the new evidence.

The...