Maj Gen Rabe Abubakar's kidnapping highlights continuing security challenges facing parts of the country.
Related stories
Trump welcomes Xi Jinping with red carpet, military honours and flyover
Japanese families ask Trump to raise abduction issue in possible talks with Kim
Germany, Netherlands and France: New European managers make their debuts
Trump-Xi summit: Here’s what’s on the agenda, and why it matters
Gaza $2.45 billion reconstruction plan. Who decides its future?
Greek PM: deal to return Parthenon marbles could still be reached with ‘political will and courage’