BERLIN (AFP) - German conservative lawmaker Andreas Schockenhoff, a foreign policy expert on Russia and France, has died at age 57, his party said on Sunday.

Schockenhoff was deputy chairman of the parliamentary group of Chancellor Angela Merkel's Christian Democrats and their Bavarian allies.

A lawmaker since 1990, he had also coordinated German-Russian affairs in the foreign ministry, often harshly critical of Moscow amid the Ukraine conflict.

"Russia is continuing its breach of international law," he told news portal Zeit Online last month, arguing for continued tough sanctions.

Schockenhoff has also been a leading proponent for deep cooperation with France.

"We have lost a smart foreign policy politician and a German-French bridge-builder," tweeted lawmaker Michael Roth, minister of state for Europe at the foreign ministry.

Conservative parliamentary leader Volker Kauder mourned the loss of one of the group's "most prominent politicians ... a good friend and close associate".

Schockenhoff died of natural causes in the night from Saturday to Sunday in his electoral district of Ravensburg in southern Baden-Wuerttemberg state.