As with the search opinion, for each objection the communication should indicate the part of the application which is deficient and the requirement of the EPC which is not met, either by referring to specific articles or rules, or by other clear indication; it should also give the reason for any objection where this is not immediately apparent (for more details see B‑XI, 3.2).[Rule 71(2); ]
The burden of proof and the onus of presentation of the relevant facts about patentability requirements lie initially with the examining division, which must provide evidence and facts to support its objection (see decision T 655/13). Accordingly, prior art documents forming the basis for novelty or inventive step objections must be cited in such a way that these conclusions can be checked without difficulty (see E‑X, 2.6).
Source: http://www.epo.org/law-practice/legal-texts/html/guidelines/e/c_iii_4_1_1.htm
Date retrieved: 17 May 2021