The Japanese unit of global mobile-phone carrier Vodafone Group Plc. said Monday that Bill Morrow, head of the group's British operations, will replace Shiro Tsuda as president just two months after Tsuda assumed the position.

In a surprise announcement, Vodafone K.K. also said Tsuda -- the former No. 2 at rival NTT DoCoMo Inc. -- would simultaneously become chairman on April 1 to form a "dual leadership structure."

The selection of someone as high-ranking as Morrow underscores Vodafone's determination to revive its operations in Japan, where it is lagging in subscriber growth.

During a news conference in Tokyo, Tsuda said he personally picked Morrow, who was not present at the conference, for his experience in the Japanese market.

The 45-year-old American led Japan Telecom Holdings -- which is now Vodafone K.K. -- as president for two years until 2003. Morrow became chief executive of Vodafone's British business in February 2004.

Tsuda said his role will not change even after Morrow starts to colead the Japanese operation.

Tsuda, 59, was invited to take over Vodafone K.K. on Dec. 1 to revamp the carrier's flagging subscriber growth.

In January, the country's third-largest carrier lost a net 58,700 customers, after subtracting those who quit from new subscribers, according to a company report released the same day.

Rivals KDDI Corp. and NTT DoCoMo have been enjoying solid subscriber growth thanks to their faster third-generation networks. Vodafone has been slow to introduce the high-speed service and is fielding a relatively poor lineup of 3G handsets.