DUNCAN MIRIRI KENYA is "disturbed" by comments about President William Ruto reportedly attributed to the United Nations deputy secretary-general in a leaked U.S. classified document, a senior Kenyan official said on Friday. The BBC, citing a leaked document, reported this week that Amina Mohammed told U.N. Secretary-General Antonio Guterres in February that Ruto was "ruthless" and that she "doesn't trust him." Nairobi is a key hub for U.N. operations. Reuters has not independently verified the document's authenticity. When asked about Mohammed's reported remarks, senior Kenyan foreign affairs official Korir Sing'oei described it on Friday as "disturbing," while also noting that…