(CNN) Republican Rep. Steve Scalise and former Democratic Rep. Gabby Giffords, both survivors of horrific shootings while serving in Congress, hugged on the floor of the House of Representatives shortly before a moment of silence on the eighth anniversary of the shooting that almost killed Giffords.

Giffords was in Washington on Tuesday, the anniversary of the shooting in Tucson, Arizona that left six dead and Giffords badly wounded, to help introduce a bill requiring background checks on private transaction gun sales. In 2011, Giffords was shot in the head during an appearance in front of an supermarket and suffered severe brain injuries

Since the shooting, Giffords has become one of the nation's pre-eminent advocates for gun control legislation. On Tuesday, Giffords joined newly elected House Speaker Nancy Pelosi and California Democrat Rep. Mike Thompson to unveil a bill to require background checks for private gun sales. Despite bipartisan support for some gun legislation proposals, the Democrats' background check proposal appears unlikely to advance in the Republican-controlled Senate.

In June 2017, Scalise, who at the time was the third ranking member of the House Republican leadership as majority whip, was shot and left in critical condition after a gunman targeted a GOP congressional baseball practice in Alexandria, Virginia.

The congressman sustained a single gunshot wound to his left hip and suffered "significant damage" to his blood vessels, bones and some internal organs, his doctor said following the shooting.

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