(Reuters) -Chinese planemaker COMAC is falling behind on previously stated delivery targets for the production of its narrow-body C919 commercial plane, according to regulatory filings from the three airlines that fly the model.

China Eastern Airlines, Air China and China Southern were expecting 32 of the planes to be delivered this year, but as of September only five have been handed over from COMAC, according to airline financial reports and data from ch-aviation and Flightradar24.

The state-owned manufacturer has cut its own C919 production target to 25 this year from a previously stated goal of 75, Bloomberg reported on Wednesday, citing sources familiar with the matter. COMAC did not respond immediately to a request for comment.

COMAC in January said it planned to deliver 30 C919 planes and scale up annual production capacity to 50 aircraft in 2025. In March, it raised the production target up to 75, according to Chinese media reports.

COMAC is seeking to compete internationally with leading Western planemakers Airbus and Boeing ( BA ), which produce dozens of their single-aisle A320neo family and 737 MAX jets each month.

COMAC this year faced the unexpected challenge of the United States temporarily halting exports of the CFM engines it uses on the C919 between June and July as trade tensions escalated. A key vulnerability of China's jet-building programme is that major elements of the designs use foreign parts.

The C919, which lacks benchmark certifications from major Western aviation regulators, has only had orders from Chinese customers and two airlines in Brunei and Cambodia - both close allies of Beijing.

Aviation consultancy IBA said last month that COMAC's C919 production targets were ambitious and it expected "more measured growth" from the manufacturer.

IBA forecast around 18 C919s would be delivered in 2025 and 25 in 2026, rising to about 45 in 2027.

China Eastern, Air China and China Southern each ordered 100 of the jets.