The rate on 30-year Treasury bonds approached an all-time low and a closely monitored section of the U.S. yield curve hurtled closer to inversion as investors sought shelter amid a fraught geopolitical backdrop.

The 30-year yield tumbled as much as 14 basis points to 2.1179%, below the level it reached last Wednesday. The record stands for the long bond at 2.0882%, which the market touched back in July 2016. Yields on benchmark 10-year notes also dropped as much as 12 basis points to 1.6284%, and the key rate at one stage fell to be to just 5.1 basis points more than the equivalent for 2-year notes -- the smallest differential for the so-called yield curve since 2007.

The rush-for-cover came as global trade concerns rumbled on and as protests in Hong Kong forced airport authorities to cancel Monday’s remaining flights, escalating tensions with mainland China. Political upheaval in Argentina added to the risk aversion as assets in the country plunged in the wake of President Mauricio Macri’s unexpected defeat in a primary vote.

“The general risk-off theme is driving the move, which is actually flattening the curve rather than steepening it,” said Gennadiy Goldberg, a senior U.S. rates strategist at TD Securities. “This suggests that the market is being driven less by Federal Reserve expectations and more by a flight to quality or global uncertainty.”

The rush to havens spread across assets, with the Japanese yen nearing a 2019 high against the dollar while gold prices rallied. Fed funds futures showed traders betting on more easing from the U.S. central bank, with around 66 basis points of cuts priced in for the rest of this year.

“There’s a lot of concern that negative rates are going to move onto U.S. shores, and that’s driving demand for duration from fixed-income investors who are looking to insulate themselves,” said Mark Heppenstall, chief investment officer for Penn Mutual Asset Management, which has $27 billion under management.

This article was provided by Bloomberg News.