United Parcel Service said it was in constructive talks to buy Dutch rival TNT Express and reiterated its intention to make an offer, having last month proposed a 9 euros per share deal worth 4.9 billion euros ($6.4 billion).

UPS, the world's largest package delivery company, said on Friday it intended to request approval of its offer documents to Dutch market regulator AFM by May 11 at the latest. It did not mention a price.

UPS was seen as unlikely to improve its 9 euros offer by a large amount, given TNT's poor results and the absence of a counter bidder.

TNT Express shares closed at 9.23 euros on Thursday, after reaching a nine-month high at 10.24 euros on February 20.

Both parties have ruled out a potential counter bid from FedEx Corp at this point, sources told Reuters on Thursday.

UPS was not expected to announce a deal on Friday and needed more time to hammer out final details, the sources said.

($1 = 0.7651 euro)

(Reporting by Gilbert Kreijger; Editing by Dan Lalor)