PHILADELPHIA -- As Vice President Joe Biden discusses gun safety with law enforcement and Democratic officials here, a new poll says majorities of Pennsylvania voters think gun-control measures backed by the administration would help prevent mass shootings.

The Mercyhurst University survey released this morning found majorities of registered voters support banning military-style assault rifles and requiring background checks for all gun sales, both proposals Mr. Obama is asking Congress to pass in the aftermath of the school shooting in Newtown, Conn.

The president has also called for prohibiting the sale and production of magazines with more than 10 rounds. The survey found most Pennsylvania voters think a ban on "large capacity" ammunition magazines would help prevent mass shootings.

Mr. Biden was charged with heading development of the set of gun-control initiatives he and Mr. Obama are now pushing. Today, he took the discussion to Philadelphia, where he is holding a private meeting with officials including U.S. Sen. Bob Casey, D-Pa.; Pennsylvania Attorney General Kathleen Kane; U.S. Rep. Allyson Schwartz, D-Philadelphia; and Philadelphia Mayor Michael Nutter.

The guest list also includes prominent law enforcement officials such as New York City police Commissioner Ray Kelly, Philadelphia police Commissioner Charles Ramsey and the chiefs of police of Camden, N.J., and Baltimore. The police chief of Wilmington, Del., where a courthouse shooting was reported this morning, was expected to attend.

The Mercyhurst poll asked registered Pennsylvania voters which of various proposals they thought would help prevent mass shootings in public places. It found support for a wide variety of measures, though some proposals engendered sharp divides between people who have a gun at home and those who do not.

Fifty-five percent of Pennsylvania voters say banning large-capacity magazines would help prevent such shootings, while 58 percent say the same of banning military-style assault weapons.

Screening proposals won more support, with 84 percent of voters saying improved mental-health screening would help, and 81 percent saying the same for requiring background checks for all gun purchasers.

Only slightly less -- 76 percent -- said depictions of violence in popular culture and video games contribute to mass shootings in public places.

Many proposals with overall majority support are favored by significantly higher percentages of people without guns at home than those with guns. While 80 percent of people without a gun in their home said they thought banning assault weapons would help prevent shootings, only 45 percent of people with a gun at home thought the same.

But strong majorities in each category -- 77 percent of people in households with a gun and 87 percent of those in households without -- said requiring background checks of all gun purchasers would aid in preventing shootings.

The poll was conducted with 485 registered voters in Pennsylvania between Jan. 30 and Feb. 6. It has a margin of error of plus or minus 4.5 percentage points.