Washington — Congress took its first, halting steps toward gun control Thursday as a divided Senate panel approved a bill that would increase federal penalties on trafficking and then began debate on more contentious issues.

The Senate Judiciary Committee voted 11-7 to approve the gun trafficking bill, which would also toughen penalties on “‘straw purchases” or guns bought for those who are prohibited by law from owning one.

Sen. Charles Grassley of Iowa, the top-ranking Republican on the panel, was the only one in his party to vote for the bill.

Sponsored by Senate Judiciary Committee Chairman Patrick Leahy, D-Vt., the gun trafficking bill has a good chance of approval by the full Senate — and even perhaps in the GOP-controlled House.

Not so other measures on the Judiciary Committee agenda, including a controversial assault-weapons and high-capacity magazine ban sponsored by Sen. Dianne Feinstein, D-Calif.

Feinstein’s legislation would ban 157 types of military-style weapons, including the Bushmaster rifle used by Adam Lanza in the Sandy Hook Elementary School shooting.

But those who owned an assault weapon before the legislation went into effect would be allowed to keep it, subject to a new requirement that it be put in safe storage to keep it out of dangerous hands.

Every Republican on the panel opposes the assault weapons ban.

Sen. John Cornyn, R-Texas, said there are “cultural differences” concerning guns in America.

“There are those who know how to use them… and then there are those who are afraid of guns,” Cornyn said.

Sen. Lindsay Graham, R-S.C., said it was a waste of Congress’ time to consider an assault weapons ban.

“It has a constitutional problem and does not solve the problem,” he said.

Even Leahy, the chief Democrat on the committee, said he wasn’t sold on the ban. “I have problems with the legislation, but I’m going to vote for it to get the matter out,” Leahy said.

Leahy’s support of the ban assures it will be voted out of the committee, composed of 10 Democrats and eight Republicans. But the ban is not expected to pass the full Senate.

Besides the assault weapons ban, the Judiciary Committee was set to vote on a bill that would expand FBI background checks on gun purchasers and another bill that would provide schools with grants to hire guards or implement other safety measures.

The background check bill suffered a setback this week as Sen. Tom Coburn, R-Okla., walked away from negotiations with Democrats over the legislation.

The Judiciary Committee was unable to complete its work on assault weapons ban and the other legislation because senior members were called to an intelligence briefing over the CIA’s capture of Osama bin Laden’s son-in-law.

“We made a good start,” said Sen. Richard Blumenthal, D-Conn., a Judiciary Committee member.

The gun bills will likely be taken up again Tuesday.

Meanwhile, Mayors Against Illegal Guns, a group founded and funded by New York Mayor Michael Bloomberg, ratcheted up a campaign Thursday in support of federal gun-control measures.

The group ran full-page ads in the Washington Post and other Capitol Hill papers touting a poll that shows Americans in key states and congressional districts support expanding FBI background checks to nearly every gun buyer.

The gun-control group is also running a public service announcement that features dozens of mayors, including Hartford Mayor Pedro Segarra.

“Basta ya,” or “enough,” Segarra says in the ad.