German Foreign Minister Heiko Maas has said Germany should welcome Turkey's elected leader President Recep Tayyip Erdoğan, as he rejected criticisms from opposition parties.

"We would be mistaken to not welcome the representatives of that state," Maas told the Rhein-Neckar-Zeitung daily yesterday, adding that the danger would be much greater if the two countries did not talk to each other.

"Erdoğan is the elected President of Turkey, whether you like the Turkish presidential constitution or not," he said.

Erdoğan is expected to travel to Berlin for a two-day visit on Sep. 28. German President Frank Walter Steinmeier's office confirmed the date Tuesday.

During the visit, his first to the country since 2014, Erdoğan will meet with German Chancellor Angela Merkel to discuss bilateral issues.

The visit is expected to play a significant role in improving the strained Turkey-Germany ties. Relations between the two countries soured over a range of issues, including Germany's tolerance of PKK and Gülenist Terror Group (FETÖ) supporters and their activities within its borders.

Earlier on July 31, Maas said that the German president's invitation to Erdoğan would be an important opportunity to discuss the current differences between Ankara and Berlin. "I believe that one has to treat an elected head of state in an appropriate manner and that is what the president has done," Maas told a press conference in Berlin.

However, some politicians, especially from the opposition, are not convinced and have criticized the visit.

Former Green Party leader Cem Özdemir said: "In my opinion, all democratic politicians who want to meet Erdoğan should be reminded of the fate of imprisoned democrats in their dungeons." He was referring to the Germans who were imprisoned in Turkey, mostly in terrorism charges.

Free Democratic Party (FDP) leader Christian Lindner said that even though she finds diplomatic encounters meaningful, this meeting was questionable due to its timing since it came shortly after the presidential elections in Turkey.

Relations between the two NATO allies hit a new low following a failed coup in 2016. Turkey has criticized Berlin for not handing over suspects linked to FETÖ, over their role in the failed coup that killed 250 people and injured 2,200 others.

During the campaign period ahead of the April 16, 2017 referendum in Turkey and ahead of the June 24 presidential and parliamentary elections, German authorities made a controversial decision and barred the Justice and Development Party (AK Party) from holding political rallies in Germany over security concerns but allowed others to campaign.