ZURICH — The Swiss central bank is ready to intervene in the currency markets again to weaken the franc if necessary, the bank’s head said, just two days after the removal of a cap on the franc triggered a surge in the currency’s value.

Swiss National Bank President Thomas Jordan said the central bank was forced to scrap its policy of keeping minimum exchange rate of 1.20 Swiss francs a euro EURCHF, +0.00% due to divergent economic developments and mounting risk from its euro-buying operations.