ZURICH (Reuters) - Swiss technology group OC Oerlikon said some financial institutions still required explanations over the United States sanctions slapped on its largest shareholder, Russian oligarch Viktor Vekselberg.

"Oerlikon has the first evidence from some financial institutions resulting in additional alignment requirements to secure current and future financial transactions," Chief Executive Roland Fischer told Reuters on Wednesday.

"We are closely monitoring the situation and are in continuous dialogue with our commercial banks," he added.

Oerlikon itself is not directly affected by the sanctions on Vekselberg, one of the oligarchs targeted by the United States as punishment for alleged Russian meddling in the 2016 U.S. election.

Oerlikon, where Vekselberg has a 43 percent stake, said customers were still placing orders.

(Reporting by Oliver Hirt, writing by John Revill; Editing by Michael Shields)