While President Obama is not ruling out an additional executive action to curb certain types of gun sales, the White House has already admitted that Obama's only remaining move on guns is to use the bully pulpit to press Congress to act.

"The president has taken substantial executive actions using as much executive authority as he can," White House press secretary Josh Earnest said Monday, acknowledging that the limits of that authority seems to have been reached.

Earnest added hopefully, "I'm not going to rule out additional steps... he's not going to hesitate to act." But Obama administration officials and Obama himself have repeatedly indicated that Obama may have exhausted his executive options on gun safety.

"The reason the president is taking these actions today is because Congress hasn't done anything," Earnest explained after Obama rolled out a package of 10 gun-related executive orders in January. "And the president has had to resort to using every element of his authority to do as much as he possibly can to try to keep guns out of the wrong hands."

Earnest acknowledged in January that Obama is essentially down to the bully pulpit. "I would anticipate that you're going to continue to see the president speak out publicly with passion on this issue," Earnest said when asked in January what more Obama can do to reduce gun violence.

Advocates for stricter gun laws agree that only Congress can do more now.

The Brady Campaign to Prevent Gun Violence has no requests of Obama, but spokesman Brendan Kelly says "there is plenty Congress can and should do," spokesman Brendan Kelly said.

Earnest said Obama will again call on Congress to reinstitute the lapsed federal ban on assault rifles in the wake of Sunday's tragedy in Orlando.

"There are certain common-sense things that Congress could do that would make it harder for any individual to get their hands on a weapon of war," Earnest said, using his preferred term for the AR-15 rifle the Orlando terrorist used to kill most of his 49 victims.

"And the president has been quite frustrated and, in some cases, even angry about congressional inaction on common-sense steps that could be taken that would make our communities safer," Earnest said, referring to Obama's big legislative push on the issue after 20 school children were killed in Newtown, Conn., in December 2012.

"I feel strongly in telling you that the president believes that it should be illegal for an individual to walk into a gun store and purchase an assault rifle," Earnest said. "It's weapon of war."

Speaking earlier on Monday, Obama hinted that he will push for the assault rifle ban, something he sought after Newtown in the 23 executive actions and three presidential memos he issued that congressional Republicans mostly rebuffed.

"We are also going to have to have to make sure that we think about the risks we are willing to take by being so lax in how we make very powerful firearms available to people in this country," Obama said after meeting with key officials, including FBI Director James Comey and Homeland Security Secretary Jeh Johnson.

But Earnest said he isn't aware of any new executive action ideas "actively" under consideration by the administration.

Earnest also chastised Congress for not acting on Obama's request to fund 200 new Alcohol, Tobacco, Firearms and Explosives Bureau positions.

"This is a proposal that president unveiled back in January [and it's] not clear to me that Republicans in Congress had even considered it," Earnest said. "That's not a progress the president is going to satisfied by, but it is progress that would save lives."

Obama will also continue asking Congress to bar people on the government's "no-fly" list from owning guns.

"Right now, it is possible for an individual who, because of their ties to terrorism, or potential ties to terrorists, is not allowed to board an airplane; but that same individual can walk into a gun store and by a gun," Earnest said.

Prohibiting them from buying guns won't "undermine the constitutional rights of law-abiding Americans, so, why would we prevent that from being a law on the books?" Earnest asked.

Congressional Democrats on Monday vowed to force the issue on the Senate floor.

The National Rifle Association, which forcefully opposed Obama's 2013 and January orders and took issue with his push for "smart gun" technology, has made no comments since the Orlando massacre.

Obama has previously blamed the group's lobbying for stymying his efforts, something Earnest repeated on Monday but which elicited no immediate NRA reaction. But on Friday, the group issued a lengthy rebuttal to Obama's swipe at the organization during a town hall in Elkhart, Ind.

Obama accused the NRA of blocking his proposal to ban no-fly list members from buying guns.

"That's right, thanks to NRA, our allies in Congress, and the basic precepts of the U.S. Constitution and liberal democracy, President Barack Obama cannot unilaterally pick and choose whose constitutional rights are to be respected," the group wrote on its website. "Would-be autocrats are still required to actually establish an individual's danger or guilt before stripping them of their fundamental rights."