Three people were killed and many injured in two explosions close to the finish line of the marathon, in an act of suspected terrorism which has shocked the US.

The S&P 500 ended the session 2.3% lower at 1,552, having hit a record high last week, while the Dow suffered its worst day of the year to shed 1.8%, and the Nasdaq closed 2.4% lower.

Asian markets continued their slide, with the Nikkei 225 falling 0.41% to 13,221 and the Shanghai Composite down 1.13% to 2,182.

The FTSE 100 lost 0.64% to close of 6,343.

Oil prices dropped in Asia, with US light crude down by 1.9%, and Brent crude sliding 1.6% to move below the $100 a barrel mark.

Mining shares took a beating yesterday as investors worried about weak economic data from China – Petropavlovsk was down more than 24% and Fresnillo lost 15% during the session. Meanwhile gold continued to fall, extending Monday’s 10% loss to hit its lowest level in two years.

By contrast, the Japanese yen gained against the US dollar as investors rushed towards the safe haven asset. Many high profile investors have been shorting the yen after the Bank of Japan’s recent aggressive stimulus measures sent the currency lower against the dollar.