According to preliminary data released on Friday, Eurozone core inflation accelerated and remained stubbornly high in June.

The 20 countries which share the euro saw headline inflation reach 5.5% this month, which was just below expectations of analysts. However core inflation, which excludes volatile energy and food, and thus can be a better measure of overall trends, surged to 5.4%, with service sector price growth also rising to 5.4%, compared to April’s 5.0% reading.

Ulrike Kastens, an economist for Europe at DWS said, “The core rate is likely to remain well above the 5% mark in the next months which will [require] further rate hikes by the ECB.”

Economists warn, that even though core inflation in the Eurozone had been dropping, from 5.6% in April to 5.3% in May, The latest rise may overpower the improvement in the headline number.

Maeva Cousin, Bloomberg’s senior economist, said, “Base effects and statistical distortions are likely to keep the core reading elevated over the next couple of months and see the ECB hiking at least until September.”

The European Central Bank will be closely monitoring inflation in the Eurozone, after hiking interest rates to the highest levels seen in 22 years on the 15th of June. In its ninth consecutive rate hike, the regulator hiked its benchmark rate by .25% to 4%.