Germany's foreign intelligence agency has been working with Russian counterparts to try to secure the release of two Israeli soldiers held by Hizbollah and another seized by Hamas, a German newspaper reported on Friday.

Foreign Minister Frank-Walter Steinmeier and Russian Foreign Minister Sergei Lavrov agreed the joint operation after the kidnap of an Israeli soldier by Hamas at the end of June, the Berliner Zeitung said in an extract from its Friday edition.

Steinmeier and Lavrov then extended the mission after Hizbollah seized the other two soldiers on July 12, said the newspaper, without naming any source for its information.

Hizbollah's action triggered an Israeli offensive in Lebanon that has killed more than 300 people. The guerrilla group, which has killed 29 people in Israel, is seeking an exchange of prisoners similar to one it made with German mediation in 2004.

Israel has also launched an offensive in Gaza Strip and the occupied West Bank to try to free the soldier seized by Hamas. It has killed some 110 Palestinians, around half of them militants.

Israel on Thursday welcomed any help Germany could give but said it would not discuss a prisoner swap.