Polish Defense Minister Radek Sikorski has resigned, apparently as the result of a political feud with President Lech Kaczynski and his twin brother, Prime Minister Jaroslaw Kaczynski.
The president's chief of staff, Aleksander Szczyglo, will replace Sikorski.
The departing defense minister indicated he was frustrated by a lack of support for Poland's military mission in Afghanistan. He told reporters he had unsuccessfully asked the prime minister to dismiss military-intelligence chief Antoni Macierewicz.
The military-intelligence officer has been criticized in Poland for his work preparing troops for assignment as part of NATO's security force in Afghanistan, but a government spokesman in Warsaw denied that was a factor in Sikorski's resignation.
Sikorski, who announced he was leaving the Cabinet Monday, was to have had a key role in upcoming talks with the United States about hosting an American missile-defense base in Poland.
Sikorski is well known in Washington, where he was a resident fellow at the conservative American Enterprise Institute before returning to Warsaw.
Some information for this report was provided by AFP and AP.