Longtime package delivery companies UPS and FedEx may have some new competition from Amazon. The company is experimenting with a new delivery service of its own intended to make more products available for free two-day delivery and relieve overcrowding in its warehouses. Bloomberg reports: The service began two years ago in India, and Amazon has been slowly marketing it to U.S. merchants in preparation for a national expansion, said the people, who asked not to be identified because the U.S. pilot project is confidential. Amazon is calling the project Seller Flex, one person said. The service began on a trial basis this year in West Coast states with a broader rollout planned in 2018, the people said. Amazon will oversee pickup of packages from warehouses of third-party merchants selling goods on Amazon.com and their delivery to customers' homes, the people said -- work that is now often handled by UPS and FedEx. Amazon could still use these couriers for delivery, but the company will decide how a package is sent instead of leaving it up to the seller. Handling more deliveries itself would give Amazon greater flexibility and control over the last mile to shoppers' doorsteps, let it save money through volume discounts, and help avoid congestion in its own warehouses by keeping merchandise in the outside sellers' own facilities.