LOS ANGELES: US lawmakers on Wednesday sought Secret Service protection for Democratic presidential candidates after Joe Biden's wife and a senior staffer shielded the former vice president from protesters during a victory speech on Super Tuesday.

Biden's remarks in Los Angeles were briefly interrupted on Tuesday night when a pair of protesters leapt onto the stage, Jill Biden and senior adviser Symone Sanders charged them and ushered them away from the candidate. The activists opposed the dairy industry, and protesters with the same agenda have disrupted events with Biden's presidential rival Senator Bernie Sanders.

"We're OK," Biden said after the incident, which highlighted a glaring hole in security for him and other top contenders seeking the Democratic nomination to take on Republican President Donald Trump in the Nov. 3 election. A Secret Service spokeswoman confirmed that no Democratic candidate was currently being protected. Any decision to provide protection would be made by Chad Wolf, acting secretary of homeland security, in consultation with congressional authorities.

No Democratic candidate has begun the multi-step process to obtain Secret Service protection, DHS spokeswoman Heather Swift said in a statement. A new procedure was established by former DHS Secretary Jeh Johnson, which requires that a candidate make a formal request, Swift said.

"The Democratic Congress is worried," Representative Cedric Richmond, a Biden supporter, told reporters on a conference call. The US House of Representatives' Homeland Security Committee requested Secret Service protection for both Biden and Sanders.

The Secret Service provides security for the president and his family, including lifetime support for former occupants of the Oval Office. Major presidential candidates are also provided with protection on a case-by-case basis. Federal law authorizes Secret Service protection for vice presidents and their families for up to six months after they leave office.

There have been a number of serious attacks on presidential candidates in the past. Senator Robert Kennedy was fatally shot in Los Angeles in 1968 after his victory in the California Democratic primary and Alabama Governor George Wallace was left paralyzed from the waist down after being shot at a campaign appearance in Maryland in 1972. - Reuters