The German government will formally recognize its loss of territories ceded to Poland in 1945 in a treaty which the German and Polish leaders will discuss Thursday at a meeting along the border, senior government sources said Tuesday.

In addition to the border treaty, German Chancellor Helmut Kohl and Polish Prime Minister Tadeusz Mazowiecki are also scheduled to discuss a cooperation treaty at their meeting in Frankfurt an der Oder, which until German unification was an East German city.The sources said the main contents of the treaties had already been agreed upon but that further consultations will be necessary to work out details.

It was not immediately clear when the treaties would be signed.

The wording of the documents will be largely based on a declaration the two leaders made at their last meeting in Warsaw last November, the sources said.

The border treaty will establish the Oder and Neisse rivers between Germany and Poland as their final border. It will also state that Germany has no claims to any territory in Poland.

After Nazi Germany's defeat in World War II, its territories to the east of the two rivers became part of Poland, which in turn lost 20 percent of its pre-war eastern territory to the Soviet Union.