Treasury bonds and related exchange traded funds advanced on their largest monthly gain since January on greater European interest after investors pushed down yields in Eurozone debt securities.

Over the past month, the iShares 7-10 Year Treasury Bond ETF (NYSEArca: IEF), which has a 7.52 year effective duration a 2.13% 30-day SEC yield, was up 1.3% while the iShares 20+ Year Treasury Bond ETF (NYSEArca: TLT), which has a 17.07 year duration and a 2.93% 30-day SEC yield, increased 3.3%.

Benchmark 10-year Treasury yields dipped to 2.33% Friday, its lowest level since June 2013, from 2.51% at the start of August. Ten-year securities have returned 2.2% over August, the largest rise since a 3.2% increase in January.

Despite expectations of a tighter Federal Reserve monetary policy, Treasuries are drawing in buyers as yields in European debt plunges to record lows amid bets the European Central Bank will enact further easing to stimulate a faltering economy and uncertainty surrounding the escalating tensions in eastern Ukraine, Bloomberg reports. [Europe’s Search for Yield to Support Treasury Bond ETFs]

“The geopolitical issues and Europe helped the market out,” Justin Lederer, an interest-rate strategist at Cantor Fitzgerald LP, said in the article. “It’s worth buying the long end. I’m hesitant of shorter maturities as we progress toward the Fed rate hike and expectations for rates to go higher.”

According to Bank of America Merrill Lynch index data, fixed-income securities from the U.S., Asia and Europe have added 1.3% in August, the most since January.

Eurozone bond yields have been declining after ECB president Mario Draghi stated that the ECB was “ready to adjust our policy stance further,” utilizing “all the available instruments needed to ensure price stability.” Benchmark 10-year German bund yields dipped to an all-time low of 0.866%.