NEW YORK — An antitrust suit aimed at blocking T-Mobile’s acquisition of Sprint opened Monday in a crowded courtroom in New York with testimony from Sprint executives that touched on the consumer benefits of the company’s competition with T-Mobile and other carriers.

A group of 14 state attorneys general, led by New York and California, aim to convince a federal judge that the $26.5 billion deal should be blocked. T-Mobile has already notched approvals from key federal regulators, setting up an unusual situation where states officials are seeking to overturn their federal counterparts.

The trial, in U.S. District Court in New York, is expected to last several weeks.