Italy’s UniCredit moved to buy another big chunk of Commerzbank, shrugging off German opposition to a possible takeover and upping the ante in its attempt to create a European banking champion with nearly $1.

Italian government officials are growing frustrated at Germany’s opposition to a potential takeover of Commerzbank AG by Milan-based UniCredit Spa, threatening to disrupt the delicate diplomatic relations between Berlin and Rome.

UniCredit is "doing well" to act within the European Union's internal market, Italian Foreign Minister Antonio Tajani told the Class CNBC network on Monday, commenting on the Milan-based bank interest for Germany's Commerzbank .