New York Mayor Michael Bloomberg, the son of Martin Luther King Jr, and a string of shooting victims entered a burning national debate over gun rights Monday with a call for stricter controls.

"Every day, 34 Americans are murdered with guns -- and most of them are purchased or possessed illegally," Bloomberg said at the City Hall event, where he was also joined by Boston Mayor Thomas Menino.

"The time has clearly come to finally fulfill the intent of the common sense gun law passed after the 1968 assassinations of Martin Luther King, Jr, and Bobby Kennedy, by creating a loophole-free background check system," he said.

A long-running national debate over gun control has flared up again with this month's wounding of congresswoman Gabrielle Giffords in Arizona and killing of six bystanders.

President Barack Obama is under pressure from advocates to use his State of the Nation speech to Congress on Tuesday to press for restrictions on the most dangerous weapons.

Bloomberg said the most essential fix Obama needs to target was proper screening of gun purchasers.

"We believe it is an opportunity for our president to make a strong pledge to fix our gun laws and shore up our background check system," Bloomberg said.

Martin Luther King III, whose black civil rights activist father was gunned down in 1968, said he too was "a victim."

"For decades we have tolerated senseless gun violence, which has struck down too many of our fellow citizens, particularly our young people," King said.

Joining the high-profile campaigners were 34 victims of gun crimes, their number representing the toll taken daily, on average, across the country.

"We need to take a stand because it's ridiculous. I'm angry. I'm very angry right now because the person who murdered my daughter has still never been found," one distraught parent said.

A mother pleaded for "President Obama to start taking action. We are having a horrible, horrible war of our own here toady. We are here not as victims but as victorious voices to stand up to gun manufacturers."