Polish Prime Minister Mateusz Morawiecki and German Chancellor Angela Merkel condemned Russia for what they called the illegal annexation of Ukraine's Crimean peninsula.
In 2014, Russia annexed Ukraine's Crimean peninsula and separatists have since been fighting in the country's Donbas region.
Nord Stream 2
Merkel and Morawiecki also discussed Nord Stream 2, a Russian planned pipeline that bypasses Ukraine as well as Poland and the Baltic States by delivering gas to Germany via the Baltic Sea, a project that has been vocally opposed by Warsaw.
Morawiecki warned that the pipeline could cause further instability in Ukraine, while Merkel said that maintaining stability in the country was important.
Morawiecki said that the pipeline could mean that Ukraine would not be a transit country for Russian gas, while Merkel said Ukraine should play an important role in gas transits from Russia.
Merkel said that Germany was preparing to increase gas purchases, adding that the country wanted to diversify supplies and build a liquefied natural gas (LNG) terminal.
Polish Radio's IAR news agency reported that US President Donald Trump has been putting pressure on Germany to purchase gas from the US and reduce its energy dependence on Russia.
The Polish and German heads of government also discussed strengthening the European Union, saying that Brexit was one of the major challenges facing the bloc.
Morawiecki said it was in the interest of both Poland and Germany for Great Britain to maintain strong political and economic ties with the European Union after they divorce next year.
But negotiations over a Brexit deal have come to a standstill as the European Union and Britain are unable to agree on the future of the border between the Republic of Ireland, a European Union member, and Northern Ireland, which will be leaving along with the UK.
Merkel said she wants a deal to be reached and would make efforts to have it happen quickly.
Morawiecki said that the bloc and Britain were on the right path to achieving a deal but that it would not be easy.
The Polish prime minister also said Warsaw would likely not be part of the United Nation's Global Compact for Migration agreement.
He said Poland shared a stance on migration with the Czech Republic, Austria and the US.
Poland, a hardline opponent of accepting asylum seekers from Africa and the Middle East, has long argued that providing aid to countries where refugees originate could slow the flow of migration.
The future of the EU
Merkel and Morawiecki also agreed that a future European Union budget should be balanced. They discussed the significance of argicultural and cohesion policies.
Morawiecki said that Poland and Germany had a similar stance on accepting Balkan states to the European Union, adding that expansion could contribute to sealing from migration the European Union's internal borders.
Poland has been a strong advocate for Balkan expansions, offering to share its experience and know-how with a number of countries from the region.
During her visit to Poland, Merkel also met with the leaders of Poland's opposition parties, Grzegorz Schetyna of the Civic Platform (PO) and Władysław Kosiniak-Kamysz of the Polish People's Party (PSL), for talks about the European Union budget, policy towards Russia in context of the conflict in Ukraine's east, and an upcoming European People's Party congress in Helsinki.
The European People's Party is the largest grouping in the European Parliament, with MEPs from some 70 parties, including Merkel's CDU, its German coalition partner CSU, as well as PO and PSL.
The Polish and German foreign ministers also met for talks in Warsaw on Friday.
Poland's Jacek Czaputowicz discussed close bilateral partnership with his German counterpart, Heiko Maas and signed a declaration on the most important issues to the two countries.
Czaputowicz also urged Germany to increase its military spending as per a NATO agreement that all members of the alliance allocated 2 percent of their GDP. (vb/di)