WASHINGTON — After a gunman opened fire at the Navy Yard today, the Senate went into recess for the day and went into lockdown mode.

At the committee level, the hearing that was expected to get the most attention this week — a Senate Judiciary review of “stand your ground” laws — was quietly postponed to an undetermined date.

“How to make sense of a tragedy like the #NavyYardShooting? We are with the victims & their families in spirit and solidarity,” Judiciary Committee Chairman Pat Leahy (D-Vt.) tweeted.

Senate Majority Whip Dick Durbin (D-Ill.), chairman of the Subcommittee on the Constitution, Civil Rights and Human Rights, scheduled the hearing “‘Stand Your Ground’ Laws: Civil Rights and Public Safety Implications of the Expanded Use of Deadly Force” six days after the acquittal of George Zimmerman in the shooting death of Trayvon Martin.

The witness list for the hearing, originally scheduled for 10 a.m. Tuesday, included three members of the House: Congressional Black Caucus Chairwoman Marcia Fudge (D-Ohio), Rep. Luis Gutierrez (D-Ill.), and Tea Party Rep. Louie Gohmert (R-Texas).

A second panel was to feature Martin’s mother, Sybrina Fulton, and Lucia Bath, whose 17-year-old son, Jordan Davis, was killed in November when a man at a gas station opened fire on his car after a dispute over loud music. The accused in the Davis case, Michael Dunn, said he shot at the Florida teen and his friends because he saw a gun in their car but no weapons were found. Dunn soon goes to trial on a first-degree murder charge.

They were set to be joined by Florida State Attorney William Meggs, who has called his state’s Stand Your Ground law a “nightmare.”

Members of Congress extended few opinions yet many prayers and polite sympathies as Monday unfolded.

“I’ve spoken with the Sergeant at Arms, and in light of the events at the Navy Yard, we will recess the Senate until tomorrow morning,” Senate Majority Leader Harry Reid (D-Nev.) said via Twitter. “My sympathies go out to the victims of the Navy Yard shooting, and we are all thankful for the professionalism of our first responders.”

The House was not in session Monday. D.C. Del. Eleanor Holmes Norton (D) will be leading a moment of silence on the floor of the lower chamber on Tuesday evening.

“I have long had a special attachment to the Navy Yard ever since we worked with the Clinton administration to bring the Naval Sea Systems Command, the first new facility to be located in the rapidly developing area. The renovation of the historic Navy Yard, which had been moribund for decades, started reinvigoration of the Capital Riverfront neighborhood,” Norton said Monday afternoon.

“I ask that we all withhold judgment on the causes and possible remedies that may be required here. This is one of the most secure sites in the District, and the Navy has kept this facility secure without closing it to the public,” she added. “Just a few years ago, the Navy built a beautiful new event center at the Navy where organizations from the city and region regularly hold events. We cannot allow events like today’s to shut down the city or keep us from engaging in normal activities.”