Oil prices tumbled more than 6% on Monday as hopes of a diplomatic breakthrough between the United States and Iran erased part of last month's rally. However, uncertainty over the negotiations and persistent security risks along key shipping routes has kept investors on edge.

Brent crude futures slipped US$5.52, or 6.28 per cent. Read more at straitstimes.com. Read more at straitstimes.com.

TOKYO/SINGAPORE: Oil prices tumbled $4 a barrel on Monday after US President Donald Trump held off on a fresh attack on Iran, seeking to reach a quick deal that would halt…