AstraZeneca offers 8 million extra doses to EU through March -source

* Under EU contract Astra committed to at least 80 mln shots in Q1

* EU funded two UK plants under deal with AstraZeneca -sources

* AstraZeneca says UK has priority for doses produced there

BRUSSELS, Jan 29 (Reuters) - AstraZeneca has offered the European Union 8 million more doses of its COVID-19 vaccine this quarter, which the EU has deemed inadequate because it would still leave a large shortfall from what was originally expected, an EU official told Reuters.

Last week the Anglo-Swedish firm unexpectedly announced cuts in supplies to the EU, citing production problems at a Belgian factory. EU officials said that meant a 60% cut to 31 million doses in the period to end-March.

The EU official directly involved in talks with the company said that AstraZeneca had later offered to increase deliveries to possibly 39 million doses in the first quarter, which the EU considered insufficient.

Under a contract agreed in August the company should have supplied at least 80 million doses to the EU in that period, the official said, and possibly even 120 million “depending on how you read the contract”.

A second EU official said in a media briefing on Wednesday that the company had proposed to supply a quarter of the agreed volume of doses through March, which in the contract amounted to a “three-digit” figure - which is consistent with the nearly 40 million out of a total of 120 million mentioned by the first source.

AstraZeneca’s chief executive Pascal Soriot told newspapers on Tuesday the company had no legal requirement to deliver to the EU on a precise timetable, because it had only committed to supplying vaccines under a best-effort clause.

At a meeting on Wednesday with EU officials, Soriot repeated this argument and made no new offer of extra doses from the 39 millions pledged earlier in the week, the first EU official said. ($1 = 0.8261 euros) (Reporting by Francesco Guarascio @fraguarascio; Additional reporting by Sabine Siebold, Paul Sandle and Ludwig Burger; editing by Catherine Evans)