MADRID, Sept 20 (Reuters) - Spain"s Santander (SAN.MC) is in negotiations with about 210 employees in Portugal as part of a wider cost-cutting plan that affects 11% of its workforce there, a source with knowledge of the matter said. Hit by the fallout from the COVID-19 pandemic, ultra-low interest rates in the euro zone and a shift by customers towards online banking, European lenders have been looking to rein in excess costs. read more According to an internal memo from June seen by Reuters, the bank is offering early retirement to employees over 55 years and a compensation package corresponding to time served. The source said that about 475 employees of a total of 685 affected by the cost-cutting plan had accepted the bank"s conditions, adding that the bank was now in negotiations with the rest. On Monday, Santander, in response to a request for comment, said its aim was to reach an agreement with staff regarding departures in Portugal, where it had 6,049 employees as of the end of June. In December last year, the banking giant reached an agreement with unions to lay off 3,572 employees in Spain as part of a cost-cutting plan, around 12% of its workforce in its home market.