NTT Docomo Inc. has strengthened its competitiveness since it began selling popular Apple iPhones in September, President Kaoru Kato said Friday.

"We are starting to see iPhones' impact on our numbers," Kato said at a news conference in Tokyo where Docomo, which has the most cellphone users in Japan, announced its April-December results.

In December alone, the carrier saw a net increase of 279,000 subscribers, topping both of its rivals, KDDI Corp. and SoftBank Corp., for the first time in two years.

Kato also said the number of subscribers fleeing Docomo for other carriers was on a downward trend in the past three months.

Meanwhile, Docomo said building up sufficient stocks and creating marketing channels took a few months, so the company did not see an impact from the iPhones as quickly as it wished and the benefit as not yet appeared in its financial results.

Operating profit in the October-December quarter fell to ¥215 billion from ¥231 billion in the same period last year.

As for its April-December results, Docomo posted ¥3.36 trillion in sales, down by 0.2 percent from the same period last year, while operating profit came in at ¥688 billion, down by 1.9 percent.