President Trump's top national security aide said Friday there is a military option for handling North Korea's missile and nuclear testing, even though it's an option the Trump administration does not want to employ.

White House national security adviser H.R. McMaster said at the White Hous that the administration again wants new sanctions against North Korea to work. But he warned that the regime's stepped up testing means that "we're out of time."

"We've been kicking the can down the road, and we're out of road," he said. "So for those who have said and commenting about the lack of a military option, there is a military option."

McMaster stressed, however, that the Trump administration is still hopeful that new United Nations sanctions against North Korea will deter the regime, and stressed that military action is "not what we would prefer to do."

"So, what we have to do is call on all nations, call on everyone to do everything we can to address this global problem short of war," he said. "So, that is implementing now these significant sanctions that have just now gone into place. And it is convincing everyone to do everything that they can — and that it's in their interest to do it."

McMaster was joined at the White House by U.S. Ambassador to the United Nations Nikki Haley, who agreed that the UN is running out of options for pursuing the "peaceful pressure" campaign that Trump's team has hoped would bring North Korea to heel.

"There's not a whole lot the Security Council is going to be able to do from here," Haley said.

Haley's comments suggest that she won't revive an attempt to push an oil embargo through the U.N. Security Council, after China and Russia opposed the measure last week. Instead, she argued that the resolution which passed instead of the more-stringent embargo would be a strong deterrent to the regime if it is implemented effectively.

"If you look at the resolutions that have passed over the last month, the two of them, they cut 30 percent of their oil, they banned all the laborers, they based 90 percent of the exports, they banned joint ventures," Haley said. "in the words of North Korea, we've strangled their economic situation at this point."

While McMaster said "we're out of time" on North Korea, he also admitted the sanctions will take time to have maximum affect. It was an apparent warning to Russia and China, both of which oppose additional U.S. military buildups in the Asia-Pacific region, yet also provide economic lifelines to North Korea.

Their comments came one day after Secretary of State Rex Tillerson called on China to implement the oil embargo unilaterally.

"China supplies essentially all of North Korea's oil," Tillerson told reporters in London. "I am hopeful that China — as a great country, a world power — will decide on their own and will take it upon themselves to use that very powerful tool of oil supply to persuade North Korea to reconsider its current path towards weapons development, to reconsider its approach to dialogue and negotiations in the future."