BERLIN (AP) — The eurozone finance ministers' new leader says Europe needs to use a "unique window of opportunity" in the coming months to strengthen the continent's common currency.

Portuguese Finance Minister Mario Centeno traveled to Germany, Europe's biggest economy, on Wednesday on his first official trip since taking over as head of the eurogroup last weekend.

In a nod to long-standing German concerns about bailing out struggling countries, he declared "we cannot create a transfer union" — which, he said, no one wants.

Centeno said there needs to be "strong euro-area institutions." He also said he sees "efficiency gains from setting up in the future a euro-area finance minister" who would be accountable to parliaments.

Germany has given a mixed response so far to the idea of a eurozone finance minister.