The European Central Bank can only pause interest rate hikes at its September meeting if it’s certain that core inflation is under control, Governing Council member Peter Kazimir said on Wednesday.

If the pace of underlying price increases persists, then there will be further monetary tightening, he told journalists at a news conference in Bratislava.

“We must have a high level of certainty, based on actual data, showing that we have core inflation under control in the near future,” he said when asked about a possible pause in hikes in September. “If core inflation continues to be stubborn, I think it’s logical that voices that want another increase in September will prevail.”

The ECB raised its inflation projections slightly last week, prompting some officials to warn rate increases may need to persist beyond the July meeting that analysts have widely flagged as the end of the euro zone’s historic monetary-tightening cycle.

Kazimir said the September decision remains uncertain.

He said that while the ECB expects profit margins in the euro zone to gradually decrease, he belongs to governors that doubt that estimate and consider this to be one of the risks, “mainly due to unregulated prices” that aren’t under control.

ECB President Christine Lagarde warned last week that higher-than-anticipated increases in wages or profit margins could drive inflation higher, including over the medium term.

“Core inflation is impacted by secondary factors — wage growth and profit margins — that could lead to a persisting price growth spiral, which we fear the most,” Kazimir said. “We must act regardless of what it does to economic growth or unemployment.”

The Slovak central bank governor added that sales under the APP program are currently not on the agenda.

“We continue to reduce the balance sheet of the Eurosystem quite successfully, this doesn’t cause any additional uncertainty or hardship with liquidity, and that’s the key,” he said.

(Updates with comments from central bank governor starting in sixth paragraph.)