* Says its unit NTT Docomo Inc bought back 75.7
shares through a takeover bid, at the price of 2,681 yen per
share, during period from Dec. 12, 2017 to Jan. 15
* Says co's unit NTT Communications Corp signs agreement to
acquire 100 percent stake in U.S.-based firm Secure-24
Intermediate Holdings, Inc (target company) on Nov. 13 (U.S.