Iran's President Mahmoud Ahmadinejad and Venezuelan President Hugo Chavez are in Havana, Cuba, for the annual summit of the Non-Aligned Movement.
Heads of state and other senior officials from the movement's more than 100 members are scheduled to meet Friday and Saturday. U.N. Secretary-General Kofi Annan also is due to address the summit Friday.
Iran's nuclear program and Venezuela's bid for a seat on the U.N. Security Council are likely to top the summit's agenda.
The six-day summit ends on Saturday.
The Non-Aligned Movement, which has 116 members, was formed more than four decades ago with the aim of avoiding alignment with the United States or the Soviet Union during the Cold War.
It is not clear if Cuban President Fidel Castro will appear at the meeting.
The 80-year-old leader has not been seen in public since the announcement July 31 that he underwent intestinal surgery and temporarily transferred power to his younger brother, Defense Minister Raul Castro.
However, Cuban television has shown video of Mr. Castro during his recuperation, including Thursday's private meeting with political ally and friend, Venezuelan President Chavez.
Mr. Chavez said Mr. Castro was "walking and singing," and joked the Cuban leader was doing so well he is almost ready to play baseball. Both men are avid baseball fans.
Some information for this report provided by AP, AFP and Reuters.