The action followed clashes between demonstrators and police on U.S. campuses and a blockade at Paris's Sciences Po university
"I would like to express my condolences to all of the relatives and family members of the children who were killed in the awful shooting in a Texas elementary school," Zelensky said as he addressed an event on the sidelines of the World Economic Forum in the Swiss resort of Davos via video link.
"As far as I know, 21 people were killed, including 19 children. This is terrible, to have victims of shooters in peaceful time," he added.