Tokyo stocks ended the morning session higher Wednesday, helped by a rise across a broad range of issues due to the yen's weakness, but the Nikkei Stock Average trimmed its early gains amid growing concerns about North Korea's recent threats against the South. The benchmark index ended morning trade at 9,546.69, up 78.65 points, or 0.83%, according to the (Nikkei) website. An overnight rise on Wall Street and the yen's weakening against the euro encouraged investors to buy exporters and a broad range of other issues on hopes for profitability improvements. But buying was muted amid growing worries about North Korea's future actions and as they awaited for the outcome of the U.S. Federal Open Market Committee meeting. The Nikkei average trimmed its gains after buying ran its course.