The bank halted its government bond purchases Friday in an attempt to slow a one-way bonds trade that's put unwanted downward pressure on the yuan, analysts say.

The unexpected action is intended to tamp down a potential bubble in the bond market fueled by investors shunning riskier assets like stocks and real estate.

China's central bank is expected to deploy its most aggressive monetary tactics in a decade this year as it tries to stimulate the economy and soften the blow of impending U.S. tariff hikes, but in doing so it risks quickly exhausting its firepower.