As Germany and Britain joined the US and France in military strike against the Islamic State militant group in Syria and Iraq, the United States has said the joint effort will ultimately destroy the terror outfit even though it will be a long and challenging fight.

White House Press Secretary Josh Earnest congratulated the UK on their strikes overnight against IS targets in Syria, and commend their ability to join this mission so quickly, following the parliamentary vote. He said United States would welcome a constructive Russian contribution to its 65 member nation counter-IS coalition.