Lawmakers of the House’s Transportation Security Committee warned on Tuesday that commercial airline flights remain a "major target for terrorism" and that dangerous "gaps in security" screenings could lead to a terrorist attack.

However, the director of TSA’s Office of Global Strategies, Joseph Terrell, offered few answers, leading to frustration and a contentious back and forth during the afternoon hearing.

These lawmakers grilled Terrell, seeking to determine how major security gaps at overseas airports could lead to an attack on the homeland.

The hearing comes less than a month after Islamic State terrorists downed a Russian commercial airliner with a bomb as it flew over Egypt.

The administration official was unable to provide answers about how Congress can increase security, telling lawmakers in a moment of candor, "Perhaps I need some time to think about it and get back to you."

The attack on the Russian Metrojet airliner represents "a shift in the threat against aviation" posed by the terror group, according to Rep. John Katko (R., N.Y.)

"There remain gaps in security that needs to be addressed," he said, citing "serious lapses in security vetting among aviation workers with access to secure and sensitive areas of airports."

"I remain very concerned with the at the overall state of airport access controls." Katko said, claiming that officials are "ignoring open back doors at airports."

Rep. Kathleen Rice (D., N.Y.) also expressed concern about the threat posed to commercial airliners, noting, "the threat of terrorist attacks is very real and the risk is very high right now."

"Commercial flights are still a major target for terrorism," she added. "We cannot afford to get comfortable or complacent right now. … There are terrorist groups and radical individuals targeting aviation."

However, Terrell, a top official at the TSA, had little to provide in the way of answers and recommendations on how to mitigate the threat.

Terrell said that when it comes to monitoring foreign airports and employees working at them, there is little the TSA can mandate due to restrictions implemented by foreign countries.

Though international regulations are in place to when it comes to screening measures, U.S. "authority does not extend into these other states, and quite often there’s a bit of resistance to what is being perceived as extraterritoriality of our requirements," he said.

Katko was not pleased with these responses, demanding several times that the TSA official tell Congress how it can help the security agency get the oversight authority it needs to boost security.

"If a mechanic breaks bad they could do something on an airplane, a problem that could only manifest itself once they’re in the air," Katko said. "Those are the types of things I’m concerned about, finding the needle in the haystack, the lone wolf, which is so vexing here in the United States with our higher standards. I worry about it doubly so in foreign countries, where their standards may not be as high as ours."

Airline officials have expressed their concerns about these types of vulnerabilities in closed door meeting with Congress.

"They were certainly concerned about that. It’s one thing they were very concerned about," Katko said. "Different countries have different standards for screening. It really is a gaping vulnerability."

Terrell found it difficult to address this issue, eliciting anger from Katko.

"According to you then there’s nothing else we need to do," the lawmaker said. "You’ve not told us one thing in all the testimony today of anything that needs to be shored up internationally that we can help you with."

"With all due respect," Terrell responded, "what we have really is just a continuum on our part of continuously trying to elevate standards."

"I understand that," Katko responded, asking again: "Is there something we can do to help you or do you not need our help?"

Terrell demurred.

"I’m an operation guy, sir. As far as what Congress can do for us I would best leave to others," he said. "I haven’t thought that one through. Perhaps I need some time to think about it and get back to you."