US delivery service FedEx has reached a deal to buy Dutch rival TNT Express for 4.4 billion euros (4.8 billion dollars), ramping up its presence in Europe as global e-commerce continues to expand.

The companies "reached conditional agreement on a recommended all-cash public offer of 8.00 (euros) per ordinary TNT Express share," a joint statement said.

"The transaction represents an implied equity value for TNT Express of 4.4 billion" euros.

The offer represents a premium of 33 percent over the closing share price of April 2, 2015 and a premium of 42 percent over the average share price over the last three calendar months.

Dutch mail service PostNL, which owns 14.7 percent of TNT Express, has agreed to the offer.

"This transaction allows us to quickly broaden our portfolio of international transportation solutions to take advantage of market trends - especially the continuing growth of global e-commerce - and positions FedEx for greater long-term profitable growth," FedEx CEO Frederick W. Smith was quoted as saying.

TNT Express boss Tex Gunning said the unsolicited offer came at a time of "important transformations" for the company.

"Our people and customers can profit from the true global reach and expanded propositions, while with this offer our shareholders can already reap benefits today that otherwise would only have been available in the longer run," he said.

The European regional headquarters of the combined companies will be at TNT Express's current headquarters at Hoofddorp outside Amsterdam, while the TNT Express hub in Liege, Belgium will be maintained as "a significant operation for the group".

TNT Express will sell its airline operations in compliance with applicable airline ownership regulations, and both companies said they were confident that any anti-trust concerns could be addressed.

They expect the deal to close in the first half of 2016.

The combined companies will seek to avoid significant redundancies, the statement said.

TNT Express operates in more than 200 countries and maintains a leading role in the road freight network in Europe. It currently employs some 65,000 people.