The Lithuanian President Gitanas Nausėda and the Portuguese President Marcelo Rebelo de Sousa arrived in Kyiv on the morning of Aug. 23, Ukraine's National Flag Day.
The visits were not announced beforehand for security reasons, and are taking place ahead of Ukraine's Independence Day on Aug. 24.
It is Rebelo de Sousa's first official visit to Ukraine. Immediately after arriving in Kyiv, the president visited Bucha and its memorial at the site of the Russian massacre of Ukrainian civilians.
Nausėda said that he was in Kyiv "to celebrate Ukraine's Independence Day together with the brotherly Ukrainian nation," and that Lithuania will support Ukraine for "as long as it takes."
Lithuania is a close ally of Ukraine. On Aug. 17, the country, together with its Baltic neighbors, Latvia and Estonia, announced it would join the Group of Seven (G7) declaration on security guarantees for Ukraine.
Portugal joined the declaration in July, which aims to bolster Ukraine's ability to resist Russian aggression. The guarantees also address sanctions, financial aid, and post-war reconstruction.
Portugal is also one of 11 members of an international coalition to train Ukrainian pilots on F-16 fighter jets, which was announced by Ukrainian Defense Minister Oleksii Reznikov at the NATO summit in Vilnius in July.