Investors scooped up safer government bonds in the U.S. and Germany on Thursday as geopolitical tensions in Ukraine boosted demand for haven assets. The buying pushed up price of the benchmark 10-year Treasury note for a fifth straight session.

Higher prices sent bond yields tumbling. The 10-year Treasury yield fell to near the lowest level of 2014. The 10-year German government bond’s yield hit a record low near 1%. The two-year German government bond yield traded at zero.

In recent trading, the benchmark 10-year Treasury note was 7/32 higher, yielding 2.447%, according to Tradeweb.

In Germany, the 10-year government bond’s yield fell to 1.073%. The U.K. 10-year government bond yield slid to 2.497%.

Falling bond yields in haven bond markets suggest geopolitical risks in Ukraine, Iraq and Gaza have clouded global economic growth, which has been stuck in an uneven and slow pace since the 2008 financial crisis.

While the U.S. economy has showed signs of gaining traction lately, investors are worried that the economic prospects in Europe could be undercut if geopolitical risks deteriorate.

“Geopolitical risks and a stumbling global economy have kept yields contained,” said Ian Lyngen, a government bond strategist at CRT Capital Group LLC. The U.S. bond market remains “attractive” versus some other comparable markets.

Russian Prime Minister Dmitry Medvedev laid out the details of his country’s response to Western sanctions on Thursday, banning imports of a wide range of foods and considering wider retaliatory measures. The European Union said a Russian ban on a range of food and agricultural imports was “clearly politically motivated,” and it could “take further action” after examining the measures.

European Central Bank President Mario Draghi said Thursday following the monetary policy meeting that heightened geopolitical risk could hurt the economy.

Data earlier this week showed Italy slipped back into a recession during the second quarter while factory orders in Germany, the biggest economy in the euro zone, trailed expectations. Germany is a main trading partner with Russia.

Investors and analysts expect the ECB to take more actions later this year to prop up the fragile economy. The ECB also confronts the risk of very low inflation, which economists warn may turn into deflation–a persistent decline in consumer prices that discourages consumer and business spending.

Mr. Draghi said Thursday there is downside risk to the economy and signaled he isn’t done in terms of stimulating the economy.

The prospect of more stimulus has sent euro-zone government bond yields lower this year, a main factor dragging down bond yields in the U.S.

“Europe seems to be holding the key for Treasurys recently–if the 10-year German bond yield keeps going lower, then it is likely that 2.4% will be broken” for the 10-year Treasury yield, said Anthony Cronin, a Treasury bond trader at Société Générale SA.

The 10-year Treasury yield touched 2.4% on May 29, the lowest level since June 2013. The yield has tumbled from 3% at the start of the year.

The overseas developments continue to overshadow upbeat U.S. reports that have pointed to the economy gaining traction from the winter doldrums. On Thursday new applications for unemployment benefits fell last week to this year’s second-lowest level, a new sign of an improving labor market.

Interest-rate strategists at U.S. big banks, including Goldman Sachs Group Inc., still expect the 10-year yield to rise to 3% at the end of the year.