WASHINGTON — Congress moved on Tuesday to honor police officers who responded to the Capitol attack, clearing a bill to give them the Congressional Gold Medal just days after word emerged that two more officers who were there on Jan. 6 had taken their own lives.

The unanimous vote of the Senate, which cleared the bill for President Biden, came after back-to-back announcements from District of Columbia police officials this week about the suicides of two of the force’s officers who were at the Capitol on the day of the riot, bringing to four the known number of officers who have killed themselves in its aftermath.

Robert J. Contee III, the chief of the Metropolitan Police Department, said on Tuesday that he could not say whether the riot was the cause of the suicides.

“Certainly we’re not able to prevent everything that happens, but I believe that we have a responsibility for our officers who sacrifice so much of themselves and their families to go out to protect the citizens of the District of Columbia,” Chief Contee said in an interview with Fox 5. “The least we can do is make sure that the mental health and well-being is cared for.”

But news of the suicides hung over the action by Congress to honor the police officers who helped defend the Capitol during the riot.

“Jan. 6 unleashed many horrors, but it also revealed many heroes,” Senator Chuck Schumer, Democrat of New York and the majority leader, said on Tuesday, just before the vote to award the officers Congress’s highest civilian honor. “A day that many of us remember for its violence, anger and destruction was not without its share of bravery, selflessness and sacrifice.”

The newly announced deaths came one week after four police officers who defended the Capitol that day testified about their experiences in excruciating detail before a special committee investigating the riot.

Two days later, Officer Gunther Hashida, 43, a member of the Emergency Response Team within the Special Operations Division who joined the force in 2003, was found dead in his residence, the Metropolitan Police announced.

Then on Monday night, the department disclosed that Officer Kyle DeFreytag, 26, a member of the force since 2016, had been found dead on July 10.

Mr. Schumer called their deaths “heaping tragedy upon tragedy.”

Officer Howard S. Liebengood of the Capitol Police and Officer Jeffrey Smith of the Metropolitan Police, both of whom defended the Capitol during the attack, also took their own lives shortly after Jan. 6. Family members and congressional representatives of both have pressed to classify their suicides as line-of-duty deaths, a move that an aide to Speaker Nancy Pelosi told The New York Times she favors, though federal and state laws governing such deaths generally disqualify suicides. Ms. Pelosi called the officers “patriots” and “heroes.”

While there is no official count, experts agree that officers are at a far higher risk of suicide than the general population, and some studies have found that more officers kill themselves than die on the job in other ways. The numbers have fueled greater attention to the mental health of officers and increasing calls to classify police suicides as line-of-duty deaths, much as most military suicides are.

Around 140 police officers were injured during the attack and 15 were hospitalized. Officer Brian D. Sicknick of the Capitol Police died of a stroke after clashing with the mob.

The Senate voted in February to award a Congressional Gold Medal to Officer Eugene Goodman, who led rioters away from the Senate chamber and directed Senator Mitt Romney, Republican of Utah, away from the mob.

The House in June expanded the measure to apply to all members of the Capitol Police and Metropolitan Police forces who were involved in the Jan. 6 response. That legislation passed overwhelmingly, though 21 far-right Republicans voted against the bill.

When Democrats brought that version up on Tuesday, nobody objected, allowing it to pass without a recorded vote, a rarity in the polarized Congress.

“I am still stunned by what happened in the House, where 21 members of the Republican caucus voted against this legislation,” Mr. Schumer said. “The Senate is different.”

Under the legislation, four Congressional Gold Medals would be issued to honor the officers: one each to be displayed at the headquarters of the Capitol Police and the Metropolitan Police, one at the Smithsonian and one at the Capitol. The plaque at the Capitol would list all the law enforcement agencies that helped protect the building.