Yüce, who is fluent in Russian, added that after the war began, they had opened the mosque's doors to everyone fleeing the Russian attacks, sheltering up to 200 people at times.
During the assault on the city, a rocket struck the mosque's garden and damaged its doors and windows, he recounted.
"This war, fought between two brothers, is really upsetting to us. We hope it ends as soon as possible, peace comes, and people continue their lives in peace," he added.
His wife, Nadia Yüce, said they had faced difficulties due to Mariupol's proximity to the Russian border.
"The first days of the war were terrible, we just heard the sounds everywhere. We were shocked and no one could believe that it is a war," she said.
She said they were happy to be in Germany now. Most Ukrainians hope to return home one day, she added.
Around 160,000 civilians are trapped in Mariupol, the mayor of the besieged Ukrainian city said on Monday.