BRUSSELS — Google, facing the prospect of formal antitrust charges stemming from an investigation in Europe into its search and advertising business, sent a letter on Monday to European regulators in an effort to settle the case and avoid a lengthy and potentially expensive dispute.

The regulators declined to reveal what was in the letter.

A Google spokesman, Al Verney, said the company had “made a proposal to address the four areas the European Commission described as potential concerns.” He added, “We continue to work cooperatively with the commission.”

Joaquín Almunia, the commissioner to whom the letter was sent, said in May that the company might have abused its dominance in Internet searching by displaying links to its own services, like Google maps or images, when it answered a query, preferring them over those of competitors. He also said Google had included material in its own search results that was copied from competitors’ Web sites that offer services like restaurant guides and travel advice.

Two other areas of concern involved how Google conducted its advertising business, including how it delivered search ads on partner sites.