Manufacturing output in the euro zone posted its strongest growth since May 2011 in December — but analysts warned that the data point to a worrying divergence between core economies in the region.
Euro zone manufacturing purchasing managers' index (PMI) rose to 52.7 in December, up from 51.6 in November, according to data from analysis firm Markit. The 50-point mark separates expansion from contraction.
Chris Williamson, Markit's chief economist, said that the data for the 18-nation region were "encouraging."
"A strengthening upturn in the manufacturing sector is helping the euro area recovery become firmly established," he wrote in a note on Thursday. "The latest numbers are consistent with production growing at a quarterly rate of approximately 1 percent at the end of the year."
While Germany, the euro zone's largest economy, saw its manufacturing PMI rise to 54.3 in December from 52.7 in November, the currency bloc's second-largest economy, France, saw its index fall to a seven-month low of 47.0 in December, down from 48.4 in November.
Jeremy Stretch, head of FX Strategy at CIBC, told CNBC Europe's "Squawk Box" that the figures pointed to a continued divergence between the euro zone's largest economies in terms of growth.
"The question point (for 2014) will be the divergence of economic performance across the euro zone this year — not only of the periphery versus the core, but the divergence among the members of the core. I'm particularly thinking about France and Germany here."
(Read more: French economy struggles as Germany strides ahead)
He added: "If you keep Germany out of the picture, where else does growth come from in the euro zone? This underline s the reliance the euro zone has on Germany both as the banker, tax payer and as the arbiter of growth in the euro zone."
(Read more: Why euro zone slowdown should worry the world)
Jim McCaughan, chief executive of asset management firm Principal Global Investors, told CNBC that he did not expect output in the euro zone to pick up anytime soon.
"If you look at Europe, there's not the policy mix, there isn't the productivity and there's a debt overhang, I just don't see where the growth is going to come from so I'm pretty cautious about Europe fundamentally," he warned.
Despite these concerns, however, manufacturing in peripheral euro zone countries also showed an upturn in December.
Spain's manufacturing index rose into expansion territory, hitting a two-month high of 50.8 in December; while manufacturing in Italy reached a 32-month high of 53.3. Even Greece saw an improvement; the contraction in industrial output narrowed, enabling its index to reach a 52-month high of 49.6 in December.