Saudi promises to cut output and limit crude oil exports to 6,6 million barrels per day - Wti above $46 a barrel, Brent up sharply.
Two metro stations involved in the explosion - Putin was in the city - A second unexploded device was found - The alleged bomber is said to be from Central Asia and has ties to Syrian fighters.
At least 10 dead - The injured would be "dozens" according to what the Russian news agency Ria Novosti announces - At least two stations involved.