Nokia said on Thursday it agreed to buy part of Panasonic's telecoms network business to boost its operations in Japan, already a key market for the Finnish company.

The deal covers Panasonic's mobile phone wireless base station system business for operators and a related wireless equipment network, Nokia said.

It did not disclose the value of the deal, which it expects to close at the start of next year.

The acquisition will "add significant value for Japanese operators," Nokia Networks executive Ashish Chowdhary said in a statement.

The deal, reported by Japan's Nikkei newspaper earlier this month, adds to a string of small acquisitions that have followed the sale of Nokia's once-mighty handset business to Microsoft in April.

Last year, Japan was the second-biggest market for Nokia's continuing operations, mainly consisting of a networks business, with sales of 1.39 billion euros. They were, however, down 36 percent from 2012.