moscow kremlin say sunday inflexibility part unite state blame lack bilateral meet russia president vladimir putin u.s. president donald trump summit vietnam trump putin meet briefly sideline asia-pacific economic cooperation summit vietnam saturday agree joint statement support political solution syria hold substantive bilateral talk unfortunately american side offer alternatives despite efforts russian colleagues one time offer convenient american side one place offer already rent americans kremlin spokesman dmitry peskov quote say ria news agency americans show flexibility unfortunately offer alternative proposals meet could happen peskov add putin say saturday lack bilateral meet trump vietnam due leaders schedule protocol obstacles team unable overcome allegations trump election campaign collude moscow last year turn voters away democratic candidate hillary clinton hamper president efforts improve frosty u.s.-russian relations putin renew denial allegations brief meet trump saturday trump previously say accusations collusion hoax kremlin u.s. blame putin-trump bilateral meet vietnam