Berlin plans to ban Pyongyang from leasing properties that belong to its embassy in the heart of the German capital, foreign ministry sources said, confirming news first reported by Sueddeutsche Zeitung newspaper and broadcasters NDR and WDR.

"We must increase pressure to bring North Korea back to the negotiating table. That means we must consistently implement sanctions imposed by the United Nations and the European Union," said foreign ministry state secretary Markus Ederer.

"In that regard, it is particularly important that we do even more to dry up the financial resources used to fund the nuclear program," he said in a statement. "The German government is in complete agreement and the responsible authorities will now take the necessary steps."

Before Germany's reunification in 1990, North Korea had diplomatic relations with Communist East Germany and owned an embassy and several buildings in East Berlin.

The embassy has continued to operate while one building has since be turned into a low-cost hotel and another into a conference center, according to German media reports.

The embassy collects "high five-digit" sums in rent for the properties leased to two operators since 2004, they say.

The United Nations explicitly banned such leasing arrangements by North Korean embassies worldwide as part of U.N. Security Council Resolution 2321, passed in November 2016 after Pyongyang's fifth nuclear test.

The resolution says: "All member countries shall prohibit North Korea to use real estate that it owns or leases for other than diplomatic or consular activities."

Tensions between North Korea and the global community have increased over the past year amid repeated missile tests by Pyongyang.

U.S. President Donald Trump warned in an interview with Reuters this month that a "major, major conflict" was possible with North Korea, but then raised eyebrows by saying he would be "honored" to meet North Korean leader Kim Jong Un under the right circumstances.