North America boss replaced on acting basis by strategy chief Niklas Heuveldop.

Ericsson’s Rima Qureshi, who has been at the company for nearly 25 years, resigned suddenly on Thursday.

Qureshi served most recently as senior vice president and head of North America at the Swedish kit maker. She has held various roles over the years, including chief strategy officer and head of the company’s CDMA business. Qureshi was also overseeing Ericsson’s all-encompassing strategic partnership with Cisco.

Ericsson said Qureshi has left to pursue another opportunity in the industry, but did not reveal where she is headed.

"Rima has been an appreciated member of our team for many years. We wish her the best in her new position," said Ericsson CEO Börje Ekholm, in a statement.

The hunt for a successor is underway, but in the meantime, Niklas Heuveldop, who currently serves as chief strategy officer and head of technology and emerging business, has been appointed as head of North America on an interim basis.

"I am pleased that Niklas can immediately step in as acting head of the market area. He has strong customer relationships and long experience after holding several senior positions on the regional team," Ekholm said.

"We will continue our work to bring the latest technology and competitive solutions to our customers in North America," he continued. "It is an exciting region with some of the worlds most advanced operators and demanding requirements."

North America is Ericsson’s biggest single region by revenue. First quarter sales there were down 10% year-on-year to 11.8 billion kronor (€1.22 billion), due mainly to the reduced scope of a renewed managed services contract. It was just one of many lowlights in what was a gloomy quarter for Ericsson.

The company has been struggling with weakening demand for network equipment. In a bid to revive its fortunes, Ericsson turned to a new CEO in Ekholm, who took the reins in January, and in March announced a sweeping restructuring aimed at increasing its focus on network hardware, OSS and BSS solutions, the IoT, and related services.