Amazon.com (AMZN) said Tuesday it plans to provide same-day and next-day delivery options to millions of US customers in more than 4,000 smaller cities, towns and rural areas by the end of the year.

The company said the number of items it has delivered on the same or following day in the US so far this year has increased over 30% compared with the same period last year.

The company also said it is investing over $4 billion to triple the size of its delivery network by the end of 2026, with a focus on small towns and rural areas. It plans to upgrade its rural delivery stations into multi-purpose hubs that store inventory.