FRANKFURT, Jan 22 (Reuters) - AstraZeneca said initial deliveries to the European Union of the COVID-19 vaccine it is developing with Oxford University will fall short of the targeted volumes because of a glitch in production.

"Initial volumes will be lower than originally anticipated due to reduced yields at a manufacturing site within our European supply chain," a company spokesman said in a written statement, declining to provide details.

"We will be supplying tens of millions of doses in February and March to the European Union, as we continue to ramp up production volumes," he added. He would not provide the initial volume target.

A decision on the EU's regulatory approval of the compound has been expected for the end of January. (Reporting by Ludwig Burger Editing by Edward Taylor)