By Andrea Shalal
BERLIN (Reuters) - Germany's foreign minister on Monday warned against pulling out of the Nord Stream 2 gas pipeline with Russia, as some lawmakers suggested using the project to punish Moscow for its seizure of Ukrainian ships and their crew off the coast of Crimea.
Annegret Kramp-Karrenbauer, a candidate to replace Chancellor Angela Merkel at the helm of her Christian Democrat party, said on Sunday one option might be to reduce the amount of gas that will flow through the pipeline from Russia to Germany under the Baltic Sea.
However, Foreign minister Heiko Maas, a member of the Social Democratic junior partners in Merkel's coalition, told reporters the $11-billion pipeline, led by Russia's Gazprom
Withdrawing political support would diminish Berlin's ability to pressure for some gas supplies to continue to be sent to Europe via Ukraine, he said.
The project aims to double capacity of the existing Nord Stream 1 pipeline from next year, bypassing traditional routes through Ukraine, but Germany has insisted Ukraine should continue to play a role - and receive revenues - for allowing gas shipments across its territory.
Merkel in August secured a pledge from Russian President Vladimir Putin on the issue, Maas said.
"Withdrawing from this project would also mean taking back this political demand," he told reporters. "It would still be built, but there would not be anyone advocating for alternative gas transit through Ukraine. That is why we consider it important to remain engaged politically."
The United States, also keen to export gas to Europe, Ukraine and a number of eastern European states, says the pipeline will harm Ukraine and leave Germany dependent on Russia for decades to come.
Juergen Hardt, foreign policy spokesman for Merkel's conservatives in parliament, criticised G20 leaders for failing to hold Putin accountable for Russia's recent actions despite Merkel's efforts in bilateral meetings.
"President Putin escaped nearly unscathed with his renewed aggression against Ukraine," Hardt said in a statement.
Russia is resisting international calls to release three Ukrainian ships seized last month in the Kerch Strait near the Crimea region that Moscow illegally annexed from Ukraine in 2014. Moscow has accused the 24 sailors of illegally crossing the Russian border, which Ukraine denies.
After meeting Putin, Merkel called on Russia to release the sailors and allow shipping access to the Sea of Azov, but she did not endorse further sanctions against Moscow.
Kramp-Karrenbauer, a close Merkel ally, on Friday said the European Union and the United States should consider banning from their ports Russian ships originating from the Sea of Azov in response to the incident.
Another contender for the CDU leadership job, Health Minister Jens Spahn, said it was important to set new limits.
"I think it's an important signal to Vladimir Putin and Russia that Nord Stream 2 is not totally unconditional and it can't be that the project continues whatever he does and how far things are escalated," he said.
(Additional reporting by Michelle Martin and Sabine Siebold; Editing by Riham Alkousaa and Mark Potter)