Oil prices rallied Monday after Iran warned the presence of US forces in the Gulf was causing instability in the region, while equities were mostly down as Donald Trump said he did not want a partial trade deal with China.
While a loosening of monetary policy by central banks is providing support to investors, they remain on edge following last week's attack on Saudi oil facilities that was claimed by Huthi rebels in Yemen but blamed by the US on Iran.
President Hassan Rouhani on Sunday hit out at a US move to increase troop numbers in Saudi Arabia, saying: "Foreign forces can cause problems and insecurity for our people and for our region."
"Hopes of a potential interim trade deal had boosted sentiment ahead of last week's China's trade delegation visit to the US, but in the end it seems that the inability to find common ground in key contentious issues such as intellectual property rights resulted yet again in an increase in tensions."