He said this at a meeting with Ukrainian Prime Minister Volodymyr Groysman on Tuesday, an Ukrinform correspondent reports.
"Estonia has been and will always remain a strong supporter of Ukrainian sovereignty and territorial integrity. We emphasize this very clearly in our bilateral relations and in the framework of international organizations and forums," Mikser said.
He also said that relations between the two countries were very close and friendly and that a packed schedule of high-level bilateral visits was a sign of that.
In particular, Mikser noted close cooperation in such areas as e-governance, development of digital technologies, and also in the field of security.
He said that Ukraine's relations with the EU are extremely important and that Estonia plays a "special role" in them, since in the second half of this year it became the presiding country of the Council of the European Union for the first time.
Groysman, in turn, thanked the Estonian foreign minister for his support of Ukraine and assured that he highly appreciates Estonia's position towards Ukraine.
"We welcome your chairmanship of the EU Council, and it is very important to Ukraine, because many issues are on the agenda of the European Union. Therefore I would like to wish your presidency to be a successful period, and I also want to emphasize that our cooperation with the EU is extremely important and strategic," Groysman said.
He also recalled that the EU-Ukraine Association Agreement entered into force on September 1 and that the current task for the Ukrainian state was its full implementation.