FRANKFURT/DUESSELDORF- German utility Uniper on Tuesday said it may have to impair a loan provided to the planned Nord Stream 2 gas pipeline if the project collapses in the face of U.S. sanctions.

"Pressure has further intensified," Chief Executive Andreas Schierenbeck said in an analyst call to discuss first-half results. Uniper earlier on Tuesday said the latest U.S. sanction efforts had increased the risk that the project could falter.

"The worst case would be, of course, if (Nord Stream 2) would never be finished and then, of course, the question is can we get our money back or not," he said, adding he expected the pipeline to go ahead as planned.

The German and Russian foreign ministers, holding talks in Moscow, lent backing to his view, with Germany's Heiko Maas insisting it was Germany's "sovereign decision" to choose where to get its energy from.

Shares in Uniper, which is majority-owned by Finland's Fortum FORTUM.HE , were down 1.7%. The group also said first-half operating profits more than doubled, citing its gas business as well as capacity market payments.

Uniper is one of the financial backers of the 9.5 billion euro ($11.2 billion) Nord Stream 2 pipeline owned by Russia's Gazprom, along with Austria's OMV, Wintershall DEA, Royal Dutch Shell and France's Engie.

It has committed to fund up to 950 million euros of the project costs. Investments made by Uniper so far are not subject to the current sanctions regime, Schierenbeck said.

But U.S. opposition to the pipeline is mounting. U.S. President Donald Trump has already signed a sanctions bill that delayed construction of the project and lawmakers are contemplating further action.

At the heart of the conflict lie U.S. concerns that Nord Stream 2, which would link Russian gas fields to western Europe, would increase the region's energy dependence on Moscow. Backers, including Germany, say the gas is needed.

($1 = 0.8488 euros)

(Additional reporting by Vera Eckert and Thomas Escritt; Editing by Thomas Seythal, Louise Heavens and Barbara Lewis) ((christoph.steitz@thomsonreuters.com; +49 30 220 133 647;))