Ukrainian President Volodymyr Zelensky has congratulated German Chancellor Angela Merkel on her 66th birthday.

Read alsoMerkel says new Russia sanctions not ruled out

"Happy Birthday, Frau Angela Merkel! Wish you good health and fortitude to withstand all the hardships of the pandemic," he wrote on Twitter on July 17.

"Thanks for the comprehensive support of Ukraine in the international arena. Relations between Germany and Ukraine will only become stronger over the years," he added.

In late May, Merkel said that the policy of sanctions against Russia should be maintained.