On Friday Finnish President Sauli Niinistö began the second day of a two-day official visit to Ukraine.
The day before, Niinistö met with Ukraine President Volodymyr Zelensky for the first time at Mariyinsky Palace, the president's official ceremonial residence in Kiev.
At a joint press conference on Thursday, Zelelnsky told reporters he had warned Niinistö about Russia's Nord Stream 2 natural gas undersea pipeline project, which is still under construction.
When completed, possibly by the end of this year, Nord Stream 2 will carry Russian LNG to Germany beneath the Baltic Sea. Several firms are involved in the international, Russian-led project, including Finnish energy company Fortum.
"Nord Stream 2 is a threat to all of Europe," Zelensky said he told the Finnish president, noting that it is important to Ukraine that its international partners do not falter in implementing sanctions against Russia.
Meanwhile, Niinistö said he had brought greetings to Ukraine from the Finnish people.
"We support you and are in solidarity," Niinistö said.
On Tuesday, the supreme court of the EU, the European Court of Justice overruled a decision to permit Russian energy firm Gazprom to deliver more gas via the Opal gas line - which connects with the Nord Stream line - to Germany, according Reuters news service.
The ruling was controversial in Poland and some eastern European countries, because Gazprom plans to sidestep legacy pipelines through Poland and Ukraine. Meanwhile, Germany defended the project, as Poland claimed that the scheme would disrupt gas supplies to the region.
Finland issued its final regional permit for the Russia-Germany pipeline in April.
Broad talks on eastern Ukraine crisis
The presidents also discussed the crisis in eastern Ukraine, which has continued for the past five years.
Zelensky said he has been working toward a resolution of the situation but fell short of making promises on reaching positive results.
The Ukrainian president reiterated his support for the Normandy Four - also known as the Normandy contact group - a diplomatic body consisting of high-level representatives from Russia, Ukraine, Germany and France, which aims to end the eastern Ukraine war.
Zelensky also mentioned the importance of the Minsk Protocol, in which Ukraine and Russia agreed to resolve the conflict in eastern Ukraine in September 2014. The agreement called for a ceasefire in the region but the truce has been violated on a nearly daily basis.
Niinistö said that since the regional conflict began in February 2014, Finland has offered assistance in establishing contacts with both the countries and is still prepared to do so.
The Finnish president also noted that he recently met with Russian and French leaders, saying that it was an honour to also meet Ukraine's new leader.
The presidents of both countries praised the cooperation between Finland and Ukraine. Zelensky, who has been president since May, expressed satisfaction with investments, energy as well as environmental projects and cooperation in education which Finland has provided.
On Friday, the second day of his visit to Ukraine, Niinistö is scheduled to speak to attendees at the Yalta European Strategy (Yes) Annual Meeting in Kiev.
This year the Yes forum invited more than 400 politicians, diplomats and dignitaries from 26 countries to discuss issues on the topic of governance for happiness and the challenges of such efforts.