UNITED NATIONS, April 23 (Xinhua) -- The over-four-year-old Yemen civil war has set the country back by 21 years and its recovery will take decades, a UN spokesman said on Tuesday, citing a UN study.

Stephane Dujarric, spokesman for UN Secretary-General Antonio Guterres, said the study released by the UN Development Programme (UNDP) also warned of an exponentially growing impact of conflict on human development.

"It projects that if the war in Yemen ends in 2022, development gains will have been set back by 26 years -- that's almost a generation," Dujarric said. "If this continues through 2030, that setback will increase by four decades."

Launching the report, UNDP Resident Representative in Yemen Auke Lootsma said, "Even if there were to be peace tomorrow, it could take decades for Yemen to return to pre-conflict levels of development."

The Armed Conflict Location and Event Data Project, focusing on political violence and protest in the developing world, has said more than 71,000 people have been reported killed, including more than 7,000 civilians, since March 2015.