In initial deals, London's blue-chip FTSE 100 benchmark index dived 1.1 percent from Friday's level at the close, to 7,324.76 points.

In the eurozone, Frankfurt's DAX 30 index sank 1.0 percent to 11,756.16 points and the CAC 40 in Paris shed 1.1 percent to 5,301.59.

Asian equities had already plummeted as the Chinese yuan fell sharply, days after US President Donald Trump's vow to impose fresh tariffs on goods from China sent trade war fears spiking.

Trump's announcement, which came on Thursday, means virtually all of the $660 billion in annual merchandise trade between the world's two biggest economies will be subject to punitive tariffs, with the latest duties to take effect September 1.

The news saw all three major Wall Street indices slump to their lowest levels since June, with the S&P 500 and Nasdaq recording their worst weekly losses of 2019 on Friday.