* Plotters aimed to strike when president in China * Army officers questioned By John Zodzi LOME, April 15 (Reuters) - Togolese security forces arrested the president's brother on Wednesday on suspicion of plotting to seize power while the head of state was overseas, the West African nation's government said. President Faure Gnassingbe cancelled a trip to China on Sunday after foreign security services warned him a strike was imminent. Togo's public prosecutor later said a planned attack on national security had been foiled. "Kpatcha Gnassingbe was arrested on Wednesday morning in Lome on leaving the United States embassy where he had sought refuge," the government's official website said. Kpatcha, who is a member of parliament and a former defence minister, was one of the chief conspirators in a plot to seize power while the president was in China, it said. Five army officers have already been questioned about the plot. After soldiers attacked and raided Kpatcha's house on Sunday night, the public prosecutor Robert Bakai said some of Kpatacha's associates would also be quizzed. Bakai said on Wednesday that an investigation had begun, but gave no more details. Faure Gnassingbe was elected leader of the world's fourth biggest producer of phospates in a violent and flawed vote in 2005, taking over from his father who had ruled the country with an iron first since seizing power in 1967. Since 2005, the former French colony, sandwiched between Ghana and Benin, has begun to emerge from the international wilderness after Gnassingbe Eyadema's authoritarian rule. The next presidential elections are scheduled for 2010. The International Monetary Fund resumed lending last year after a 14-year hiatus, while the European Union restarted economic cooperation with Togo in 2007, also for the first time in 14 years. The Paris Club group of sovereign creditors cancelled $22 million owed by Togo in January, adding to a $347 million write-off in June last year. (Writing by Daniel Magnowski; Editing by David Clarke and Louise Ireland)