BRUSSELS, Dec 18 (Reuters) - European Council President Donald Tusk said on Friday the proposed Nord Stream-2 pipeline extension did not meet EU energy rules on supply diversification and would undermine Ukraine’s role as a gas transit state.

Poland, together with a group of other countries, called for Nord Stream to be debated at summit talks in Brussels and a document endorsed by the meeting said the project must comply with EU law, but it would be up to the European Commission to make a final ruling.

Tusk said that from his perspective, Nord Stream-2, which would double the amount of Russian gas shipped directly to Germany, flouted EU rules on diversifying energy supplies, energy sources and energy transit routes. (Reporting by Barbara Lewis, editing by Robin Emmott)