The United States and Britain last week added several Russian banks to their sanctions list, while the European Union cut off more banks from the SWIFT global payments system, among them online lender Tinkoff and the private Alfa Bank, both on Russia's list of systemically important credit institutions.

Those sanctioned last week have responded in a largely relaxed manner, with some saying disruption will be limited and others restricting foreign currency transactions or suspending euro trading on brokerage accounts.

Tinkoff, owned by TCS Group Holding, said it was suspending euro trading, but that the measures would not affect its more than 26 million customers.

"We ... have developed an infrastructure solution that will allow clients to seamlessly transfer [foreign] assets to a new, non-sanctioned company within one to three weeks," its brokerage arm Tinkoff Investments said.

Russia's major banks have rallied after an initial hit from last year's Western sanctions and now jostle for business from the state, particularly a burgeoning defence budget, and big corporate accounts.

Analysts at the Finam brokerage said that "a lot of work has been done over the last year to reduce operational risks and create reserves". Sanctions have mostly hurt Russians wanting to travel abroad or hold foreign currency.

However, Dmitry Polevoy, head of investment at Locko-Invest, said restrictions on foreign currency payments had deprived the largest second-tier banks of a competitive advantage over the big state banks, adding:

"In the future, this could raise the issue of voluntary and compulsory consolidation of the sector."

At a financial forum, Anatoly Aksakov, head of a parliamentary financial committee, said Russia's banking sector would not be fully disconnected from SWIFT.

"They will leave a loophole for themselves because Russia is too serious a participant in international financial relations," TASS quoted Aksakov as saying.

Alexander Shokhin, Russia's top business lobby chief, was more cautious, saying the situation could change rapidly, and that Russian banks needed to act pre-emptively.

(Reporting by Elena Fabrichnaya and Alexander Marrow; additional reporting by Vladimir Soldatkin; Editing by Kevin Liffey)

By Alexander Marrow and Elena Fabrichnaya