Mexican congressman Ricardo Monreal delivers a speech prior to the Mexican president's inauguration on December 1.

STORY HIGHLIGHTS

• A group of suspected hitmen are arrested in Mexico City
• They are accused of plotting to kill two brothers who are lawmakers
• Authorities did not reveal a possible motive

(CNN) -- Mexican authorities say they've foiled a plot to assassinate two lawmakers.

A group of suspected hitmen was arrested at a Mexico City hotel and accused of planning to kill Rep. Ricardo Monreal and Sen. David Monreal, brothers who are both federal legislators, Mexico's Attorney General's Office said.

Authorities did not reveal a possible motive or specify how many people were arrested.

Both lawmakers are from Mexico's Zacatecas state.