He will arrive in London after a brief stopover in Belarus, and returns to Moscow via Ukraine.

BBC: Putin seeks UK 'co-operation'

The development of this market an international one, centred on Washington and London, but hiring former soldiers from as far afield as Fiji, Nepal, Ukraine, Russia and Bangladesh is the result of fundamental change in military organisation.

ECONOMIST: An unregulated and unsupervised semi-covert world

Previously, Ms. Gottemoeller served as Deputy Director of the International Institute for Strategic Studies in London from 1994 to 1997 and as the National Security Council Director for Russia, Ukraine, and Eurasia Affairs at the White House from 1993 to 1994.

WHITEHOUSE: President Obama Announces More Key Administration Posts

"We are talking about the gas supply of Ukraine, " says Tom Mayne, a researcher for Global Witness, a London-based non-governmental organization that tracks corruption.

FORBES: The Energy Underworld