Russian President Dmitry Medvedev said Friday that finding the killers of two rights activists slain this week in Chechnya was the most important task at hand for all law enforcement agencies.

Medvedev said the killings of Zarema Sadulayeva and her husband, Alik Dzhabrailov, were meant to destabilize Russia's Caucasus, and were a challenge to the Kremlin-backed regional president of Chechnya, Ramzan Kadyrov. Medvedev spoke in the Black Sea resort of Sochi, where he met with German Chancellor Angela Merkel.

"The Chechen president should do everything in his power to find and punish these killers," Medvedev said.

Merkel visited Medvedev to discuss energy, business — and Russia's human rights record.

The two leaders discussed possible Russian investment in struggling German shipbuilder Wadan. German papers reported earlier this week that Russia's former energy minister Igor Yusufov is among the potential buyers.

Merkel said investment in Wadan could benefit Russia's economy.

"I have the impression that there is now a common interest and that it is possible that Wadan can build ships that Russia needs," she said.

There were no numbers given as to how many jobs could be saved at the shipyard through the deal, which comes as Merkel faces a Sept. 27 election. The shipyard is a major employer in Merkel's constituency.

In another deal, Canada's Magna and Russian Sberbank announced Thursday that they had reached general agreement with GM to buy German unit Opel.

The details of the deal have not been disclosed. It was reported earlier that Sberbank insisted that the deal would allow it to use Opel's intellectual property — something the German producer was reluctant to give away.

The Russians, however, hope Opel's technology will get the Russian car industry out of its deep slump.

Medvedev said the deal could help modernize Russia's economy. Analysts say Russia is in a deep recession because its economy is chiefly commodities-based, and not sufficiently diversified.

Germany is Russia's key partner in the Nord Stream project, a pipeline to deliver Russian gas under the Baltic Sea directly to Europe. As an increasing number of Germany's EU neighbors have raised environmental concerns about the project and say that the pipeline would increase Europe's dependence on Russia for gas.

Following this year's dispute between Ukraine and Russia, which resulted in a two-week suspension of Russian gas to much of Europe, concern about Russia's reliability has risen. The Kremlin is likely to push Germany to boost its backing of Nord Stream.

Merkel stressed that Germany is still interested in progress on Nord Stream but is also working on other natural gas projects.