Google announced several small upgrades to its flagship search service Thursday in a public event that also attempted to soothe concerns over the scrutiny it’s facing from regulators.

The Justice Department is expected to file an antitrust lawsuit against the Mountain View, Calif., tech giant in the coming weeks, the first of its kind against a big tech firm in decades. That suit is expected to focus, at least partly, on Google’s dominance in online search.

During the company’s streaming Search On event, head of search Prabhakar Raghavan pointed to one of Google’s most common defenses — that people have a lot of options to find information.

“There’s never been more choice and competition in the way people access information,” he said.

Google makes thousands of small changes to its search engine every year and has been investing heavily in artificial-intelligence research to power its service. Last year, the company announced what it said was the biggest change to its search algorithm with a software tweak to better interpret sentences.

Google has also come under fire for promoting its own products on search results pages, burying competitors’ services under Google travel results or shopping or YouTube videos. The company has acquired dozens of smaller companies over the years to build out these products — deals regulators have investigated but largely allowed to proceed.

Google has said repeatedly over the past few months that its services are beneficial for users.

The announcement Thursday came in the form of a prerecorded video with several Google executives.

During the event, Google announced new search features that allow users to index videos and quickly find the best place to start a video — for example, when a baker is adding sugar to cookies in a cooking video. The company said it expects about 10 percent of searches to use the new technology by the end of the year.

Google also debuted a feature that allows people to hum into their phones to search for songs they can’t get out of their heads, and it announced new updates to its Maps tool so users can quickly see updated local business information.

The company is facing antitrust concerns from multiple agencies in the United States, including Congress, the Justice Department and a coalition of states.

Google controls about 90 percent of the search market share. In a congressional staff report released this week, investigators found Google engaged in anti-competitive tactics.

The findings suggested Google sometimes prioritizes its own products over competitors in its search service, even if they are not superior. Some rivals have accused Google of forcing them to pay for advertisements to get their services to show up in searches above Google’s own.

Google executives did not directly address the concerns during the event Thursday.