In after-hour trading, German Bunds fell along with longer-dated Treasury prices after the Fed said it would only purchase mortage-backed securities rather than the Treasuries as many had expected, but later recovered given the scope of the plan.
The Fed said it was not likely to raise overnight interest rates from their current near-zero level until at least mid-2015, compared to its previous late-2014 guidance, and that it would pursue an easy monetary policy "for a considerable time" even after the economy strengthened.
German Bund futures were 44 ticks lower on the day at 139.86, having rallied in the previous session when concerns about Greece resurfaced.
"We sold off on the fact that they weren't buying any more Treasuries but then the fact that it's pretty open-ended and they have extended a zero-rate pledge, we bounced back," one trader said. "We could get some noise out of the (euro zone finance ministers) meeting."
Investors were also cautious, with euro zone finance ministers poised to discuss whether Spain should ask for financial support.
The announcement last week of the European Central Bank's bond-buying plan, which is conditional on countries asking for help, has ramped up pressure on Spain to ask for a rescue just as its borrowing costs have fallen on promises of intervention.