Wargaming has shut its WG Cells mobile gaming studio in Bellevue, Washington, cutting about 64 jobs, according to a report in Geekwire.

Cyprus-based Wargaming told Geekwire that it was shutting the WG Cells studio, formerly called DropForge Games, just a year after getting it started. It’s a sign of how hard it is to survive in the $36 billion mobile game market, where there’s a ton of competition and acquiring users has become very expensive.

David Bluhm, CEO of WG Cells and cofounder, told the publication that Wargaming decided it was too expensive to operate a mobile development studio in the U.S.

“Mobile gaming is a very difficult market right now,” Bluhm said. “The expertise needed and the cost centers don’t necessarily line up with where we are at right now, in the view of Wargaming.”

Wargaming still has a major PC game studio in Redmond, Washington, as it acquired Chris Taylor’s Gas Powered Games in 2013.

WG Cells built mobile games including Loot & Legends, Fantastic Plastic Squad, and Smash Squad. Wargaming has been riding high on its PC games such as World of Tanks, World of Warships, and World of Warplanes. Those games have allowed it to grow to thousands of employees.