Washington (CNN) - Hours after the Washington Navy Yard shooting, some of Washington's most vocal advocates for gun control started to renew their calls for further restrictions on firearms.
Sen. Dianne Feinstein, one of the strongest proponents of a ban on assault weapons like the AR-15 that suspected shooter and military contractor Aaron Alexis is believed to have used, issued a statement Monday asking "When will enough be enough?"
"Congress must stop shirking its responsibility and resume a thoughtful debate on gun violence in this country. We must do more to stop this endless loss of life," the California Democrat said in the statement. (Read Feinstein's statement below.)
It remains unclear exactly what happened at the Navy Yard Monday, with no indication of where the weapons used came from.
Fellow Democratic Sen. Jay Rockefeller of West Virginia did not go quite as far as Feinstein in his calls Monday for gun control. But the sentiment was there in the statement Rockefeller put out that also expressed his sorrow at the tragedy. (Read Rockefeller's statement below.)
"We are becoming far too familiar with senseless, tragic violence. This is the seventh shooting since 2009, and these repeated incidents demand our attention," Rockefeller said.
Efforts to push gun control legislation through Congress led by Vice President Joe Biden have stalled since the Sandy Hook tragedy that saw 20 school children and six adults murdered in Newtown, Connecticut last December.
CNN's Dana Bash reports that the Navy Yard shootings and several other mass shootings in the last 10 months are unlikely to undo the stall. Bash spoke to Democratic Sen. Joe Manchin of West Virginia, who told her he simply doesn't think the latest incident will be enough to garner the 60 votes a gun control measure would need to break a Republican filibuster.
Universal background checks have already proven political dead weight for Democrats at the state level, with the successful recall elections of two Colorado state legislators in Democratic-leaning districts last week.
The National Rifle Association did not respond to a request for comment Monday. The gun rights organization has typically not responded to similar shootings immediately.
– CNN's Dana Bash contributed to this report.
Statement from Feinstein:
"I mourn those killed today at the Navy Yard in Washington and send my thoughts and prayers to those families grieving the loss of loved ones.
"There are reports the killer was armed with an AR-15, a shotgun and a semiautomatic pistol when he stormed an American military installation in the nation's capital and took at least 12 innocent lives.
"This is one more event to add to the litany of massacres that occur when a deranged person or grievance killer is able to obtain multiple weapons-including a military-style assault rifle-and kill many people in a short amount of time.
"When will enough be enough?
"Congress must stop shirking its responsibility and resume a thoughtful debate on gun violence in this country. We must do more to stop this endless loss of life."
Statement from Rockefeller:
“West Virginians everywhere today are grieving for those killed-and the families they left behind-after today’s horrendous act, made all the more terrible because it happened in a place and to people who serve our nation and work to protect us.
“We are becoming far too familiar with senseless, tragic violence. This is the seventh shooting since 2009, and these repeated incidents demand our attention. While the details are being sorted out, I hope you’ll join with Sharon and me in offering our deepest sympathies and heartfelt prayers to those affected by today’s horrific act of violence.”