(Reuters) -Spirit AeroSystems posted deeper quarterly losses on Wednesday and said it was burning through dwindling cash reserves, as a strike by Boeing U.S. factory workers hammered the finances of its biggest supplier.

Spirit said in its third-quarter results that it had drawn down an entire $350 million bridge loan set up when Boeing agreed to acquire the supplier in June, confirming an earlier report from Reuters.

The supplier said it had not received $425 million in cash advances it was expecting from Boeing under a memorandum of understanding signed in April, leaving it with just $218 million in reserves at the end of the third quarter after the loan was drawn.

Spirit shares fell 4% in after-hours trading following the release of its results.

Boeing did not immediately respond to a request for comment about the cash advance. Earlier on Wednesday, Boeing CEO Kelly Ortberg said on an earnings call that there was "no change" to its planned acquisition and integration of Spirit.