The choice of the city of Gdansk, which has been both Polish and German at various points in its history, was seen as an attempt to lay historic tensions to rest.

After their brief meeting and a walk through the Baltic Sea port, the two leaders pledged closer cooperation on issues such as history, cooperation on the EU level and climate change.

"The Chancellor and I are convinced that our efforts to bring our relations to the right level of trust and cordial cooperation are bringing results," centrist Prime Minister Donald Tusk said in a joint news conference.

Cordiality was not always the watchword between the two neighbors, particularly under previous Prime Minister Jaroslaw Kaczynski. Under him, German-Polish relations became strained and the prime minister's critics accused him and his brother Lech, who is still the Polish president, of fomenting anti-German sentiment linked to the Nazis' invasion of Poland in 1939.

Tusk won elections last October, ousting Jaroslaw Kaczynski's conservatives.

Museum and the environment

Tusk said he and Merkel discussed Polish plans to construct a World War Two museum in the city.

"As soon as the concept (of the museum) is ready, we will start inviting European countries, Germany among them, to cooperate," Tusk said.

Merkel said German would gladly participate. "I think this is very exciting, a very good idea that we can all learn from," she said.

The two leaders also discussed Warsaw's worries that EU plans to cut greenhouse gas emissions could hurt Polish economic growth. Environmentally unfriendly coal provides Poland with 95 percent of its energy.