The question of China
Asked about China and its longtime close relationship with North Korea, he said the country could play a key role in persuading the North Korean government to engage in "restraint," but "they could do more."
Senators expressed concerns, skepticism and outright criticism of China. Sen. Lindsey Graham, R-South Carolina, called the country "a communist dictatorship" that fears individual freedoms.
Locklear regards China as neither a friend nor a foe.
He said that sometimes, China can be "more nuanced" than the United States, and he noted some reporting that the leadership in China has made some statements about the issue.
Over the weekend, Chinese President Xi Jinping was quoted as saying that no nation "should be allowed to throw a region and even the whole world into chaos for selfish gain." While he didn't mention North Korea, the comments were seen as a reference to Pyongyang.
"There no benefit to the Chinese of having this type of activity occurring on their borders, no possible benefit that I can see from this. So they will, I believe, in time, work this problem to their national interest just like we do and the South Koreans do," Locklear said.
The saber rattling is making an impact, poll says
Meanwhile, the storm of warlike words coming from Pyongyang appears to have rattled Americans, with more than four in 10 saying they see the reclusive nation as an immediate threat to the United States, a new CNN/ORC International poll shows.
That's up 13 percentage points in less than a month, CNN Polling Director Keating Holland said.
"If North Korean leader Kim Jong Un wanted to get the attention of the American public, his strategy is starting to work," Holland said.
North Korea's unnerving message advising foreigners to secure shelter or evacuate in case of hostilities came as Japan set up missile defenses in Tokyo and North Korean workers failed to turn up for work in the industrial complex jointly operated by North and South Korea.
In the statement published by state-run media Tuesday, the North's Korea Asia-Pacific Peace Committee reiterated accusations that Washington and Seoul are seeking to provoke a war with Pyongyang.
"Once a war is ignited on the peninsula, it will be an all-out war," the committee said, adding that North Korea doesn't want foreigners in South Korea to "fall victim" to a conflict.
But staff at the British Embassy in Seoul appeared unimpressed.
"We are not commenting on the specifics of every piece of rhetoric from North Korea," said Colin Gray, head of media affairs at the embassy. "Our travel advice remains unchanged. At this moment, we see no immediate threat to British citizens in South Korea."
And foreign visitors in Seoul didn't appear to be panicking Tuesday.
"I am concerned, but not enough not to make the trip," said Vicky Polashock, who was visiting from Atlanta.
Threat after threat
North Korea has unleashed a torrent of dramatic threats against the United States and South Korea in recent weeks, including that of a possible nuclear strike. But many analysts have cautioned that much of what Kim's regime is saying is bluster, noting that it is believed to still be years away from developing an operational nuclear missile.