German Chancellor Angela Merkel and Russian President Vladimir Putin reaffirmed their sharply different views of Russia's treatment of imprisoned Kremlin critic Alexei Navalny, democratic values and other major topics of dispute Friday but vowed to maintain a dialogue.

Merkel traveled to Moscow as she is nearing the end of her almost 16-year-long leadership of Germany. Despite deep disagreements, she has tried throughout her tenure to preserve close contacts with Putin, who has been in power for more than two decades.

Their meeting Friday came on the anniversary of Navalny falling gravely ill on a domestic flight over Siberia from what European officials would later say was poisoning with a Soviet-developed nerve agent. After the opposition leader was stricken, he was flown to Germany for medical treatment at his wife’s insistence and spent five months there recuperating.

Navalny, who is Putin’s most outspoken critic, blamed the Aug. 20, 2020 attack on the Kremlin – an accusation that Russian authorities reject. Upon his return to Russia in January, he was immediately arrested and handed a 2½-year prison term for violating the terms of a suspended sentence from a 2014 embezzlement conviction that he dismissed as politically motivated.

Speaking after Friday's talks with Putin, Merkel reiterated a call for Navalny's release, pointing out that the European Court of Human Rights had criticized his 2014 conviction as "clearly disproportionate and unacceptable."

Putin rejected the criticism, arguing that Navalny's sentencing wasn't connected to his opposition activities.

"He was convicted of a criminal offense, not his political activities," the Russian leader said, customarily avoiding mentioning Navalny by name. "No one should use political activities as a cover for conducting business projects in violation of the law."

Putin also rejected the accusations of a crackdown on Navalny's allies in the run-up to Russia's Sept. 19 parliamentary election. As he has before, he attempted to turn the tables on the West by pointing to the prosecution of people who participated in storming the U.S. Capitol in January.

Putin also scathingly criticized the West over Afghanistan, saying that the Taliban's rapid sweep over the country has shown the futility of Western attempts to enforce its own vision of democracy.

"It's necessary to stop the irresponsible policy of enforcing its own values on others and attempts to build democracy in other countries based on outside models without taking into account historic, ethnic and religious issues and fully ignoring other people's traditions," he said.

Merkel, meanwhile, urged Russia to use its contacts with the Taliban to press for Afghan citizens who helped Germany to be allowed to leave Afghanistan.

Another item on the agenda was the situation in eastern Ukraine, where Germany and France have sought to help broker a peaceful settlement to end the fighting between Ukrainian forces and Russia-backed separatists that has killed more than 14,000 people since 2014.

Merkel, who plans to visit Kyiv on Sunday, made clear that she hasn’t given up hope of progress in the coming weeks on long-stalled peace efforts in eastern Ukraine.

"I will work until my last day in office so that the territorial integrity of Ukraine can be ensured," she said.

Putin pointed at the increasing number of cease-fire violations in eastern Ukraine and asked Merkel to reaffirm to Ukrainian authorities during her upcoming trip the importance of honoring their obligations under a 2015 peace deal brokered by Germany and France in Minsk, Belarus.

"We have not yet achieved the aims we wanted to achieve in the Minsk agreement, but it is the format for talks that we have ... and we should deal carefully with this format so long as we don’t have anything else," Merkel said. "Every little bit of progress could be important, but the work we have to do is very, very hard, and there have been disappointments of the most varied kind."

The German leader and Putin also discussed the nearly finished Nord Stream 2 pipeline that will carry natural gas from Russia to Germany. The project has angered the United States and some European countries, but the U.S. and Germany announced a deal last month to allow its completion.

Putin, who said that just 15 kilometers (about 9 miles) need to be finished, emphasized that the new pipeline offers a much cheaper and safer transit route for Russian gas supplies to Germany and other EU nations.

Merkel emphasized her desire to see Russia extend its transit contract to pump its gas via Ukraine after the current deal expires in 2024. Putin said Russia stood ready to negotiate an extension of the deal but noted that specific details, such as transit volumes, would depend on market demand for the Russian gas in Europe.

Other topics the two longtime leaders discussed included stabilizing Libya, the situation in Syria, efforts to help revive the Iranian nuclear deal and developments in Belarus, where authoritarian President Alexander Lukashenko has relentlessly cracked down on dissent. Three of Belarus' EU neighbors – Lithuania, Poland and Latvia – have accused Belarusian authorities of encouraging a flow of migrants to destabilize the EU.

Merkel, 67, who grew up in communist East Germany and is fluent in Russian, has always stressed that relations with Russia can only improve through dialogue.

Her visit to Moscow could be one of her last trips abroad as chancellor since she is not running in Germany’s national election next month. It’s not clear when she will step down, because the outgoing government remains in place until a new one is formed.

Putin, 68, speaks fluent German that he polished while serving as an officer in the Soviet KGB secret service in East Germany during the 1980s. He hailed Merkel’s role in developing Russian-German ties and said she would be always welcome to visit after she steps down.

"Germany is one of our key partners in Europe and the entire world thanks to your efforts over the past 16 years," he said.

"Even though we certainly have deep differences today, we speak to each other – and that should continue to happen," Merkel said during the Kremlin talks.