Police in the Mexican border state of Baja California say they have detained 21 suspected hitmen in connection with a shooting incident near the border with the western U.S. state of California.

Authorities said the suspects were taken into custody late Tuesday, after two Mexican federal agents were shot and seriously wounded at a gas station in the city of Tecate. Officials also said that rifles and uniforms were among the items seized following the arrests.

Investigators have linked the men to Teodoro Garcia Simental, who is on Mexico's list of most-wanted drug trafficking suspects.

The arrests come about one week after U.S. Attorney General Eric Holder and Homeland Security Chief Janet Napolitano visited Mexico to discuss growing drug-related violence. U.S. President Barack Obama is expected in Mexico next week.

The White House has said President Obama is concerned about the increased level of violence in Mexico and its impact on both the U.S. and Mexico.

Drug-related violence in Mexico has killed more than 7,000 people since the start of last year. U.S. officials also say Mexican drug cartels have a presence in more than 200 U.S. cities.

Some information for this report was provided by AP and Reuters.