Last week, a Russian armored personnel carrier rammed a U.S. Mine-Resistant Ambush Protected vehicle in Syria. China test-fired "carrier killer" missiles into the South China Sea. A massive Russian nuclear submarine surfaced off Alaska, and Russia fighters hit the afterburners to come within 100 feet of a B-52 Stratofortress bomber.
The U.S. has warned that the recent spike in incidents exceeds the usual tit-for-tat testing of defenses and readiness that has gone on for decades and poses the risk of escalation into open conflict.
According to North American Aerospace Defense Command (NORAD), the number of Russian warplanes entering the Alaskan Air Defense Identification Zone (ADIZ) has increased this year.
F-22 Raptor fighters were scrambled to intercept three groups of two Tu-142 Russian maritime patrol aircraft that entered the ADIZ on Aug. 27, NORAD said in a statement.
The Russian aircraft loitered within the ADIZ for approximately five hours and came within 50 nautical miles of Alaskan shores but remained in international airspace, according to NORAD.
"Our northern approaches have had an increase in foreign military activity as our competitors continue to expand their military presence and probe our defenses," said Air Force Gen. Glen D. VanHerck, the NORAD commander.
"This year, we've conducted more than a dozen intercepts, the most in recent years," he said. "The importance of our continued efforts to project air defense operations in and through the north has never been more apparent."
The NORAD statement came on the same day that U.S. Northern Command said it was "closely monitoring the Russian submarine that surfaced near Alaska" in waters where a Russian official said its warships had never operated before.
The submarine, which appeared to be the Omsk -- a 500-foot, nuclear cruise missile sub -- was part of war games by more than 50 warships and about 40 aircraft in the Bering Sea, Adm. Nikolai Yevmenov, Russia's navy chief, said in a statement to the Russian Defense Ministry.
"We are holding such massive drills there for the first time ever," Yevmenov said.
In a blunt warning over the U.S. Navy's continuing freedom of navigation operations in the South China Sea, China last week test-fired at least four land-based, medium-range missiles dubbed "carrier killers" as part of wide-ranging military exercises.
In an Aug. 27 statement, the Defense Department said, "Conducting military exercises over disputed territory in the South China Sea is counterproductive to easing tensions and maintaining stability."
The statement noted "the firing of ballistic missiles around the Paracel Islands in the South China Sea."
China's state-run media said the missiles were DF-21D and DF-26 missiles, both of which have been touted in Chinese propaganda as highly accurate, maneuverable in flight and able to hit ships moving at sea.
"China's DF-26 and DF-21D are the world's first ballistic missiles capable of targeting large and medium-sized vessels, earning them the title of 'aircraft carrier killers,'" the state-run Global Times said.
The level of provocation in the incidents also appears to be increasing. Last Friday, two Russian Su-27 Flanker fighters flew alongside a B-52 conducting "routine operations" over the Black Sea and then hit the afterburners to pass repeatedly within 100 feet of the bomber's nose, according to video of the incident and a Defense Department statement.
Air Force Gen. Jeff Harrigian, commander of U.S. Air Forces Europe-Air Forces Africa, said in the statement, "While the Russian aircraft were operating in international airspace, they jeopardized the safety of flight of the aircraft involved. We expect them to operate within international standards set to ensure safety and prevent accidents."
Military analysts agree that incidents in which the Russian and Chinese militaries appear to challenge the U.S. presence are increasing, but differ on what they indicate.
Russia has taken more aggressive actions, but "we're seeing the same behavior from China," said retired Adm. James Stavridis, the former NATO commander.
Both Russia and China are seeking to take advantage "as America turns inward" under the "America first" policy of President Donald Trump, Stavridis said Sunday on MSNBC.
"It is definitely an escalation" in provocative actions, he added.
Most of the recent incidents "have been relatively routine, but some have been new and dangerous," said Mark Cancian, a retired Marine colonel and a senior adviser at the Center for Strategic and International Studies.
He cited as particularly concerning the incident in northeast Syria last week in which an armored personnel carrier in a Russian military patrol allegedly rammed a U.S. vehicle, injuring at least four troops.
The U.S. and Russian militaries coming into direct contact on the ground is "especially worrying" and poses the most risk of getting out of control, Cancian said.
"Unsafe and unprofessional actions like this represent a breach of deconfliction protocols, committed to by the United States and Russia in December 2019," John Ullyot, a spokesman for the White House National Security Council, said in a statement at the time.
"There's a long history of these kinds of incidents" in which the militaries of the U.S., Russia and China come in close contact, but there are procedures in place to prevent them from escalating, Cancian said.
The latest incidents, however, reflect Russia and China's intentions to demonstrate that they are military powers capable of confronting the U.S., he added.
Cancian disagreed with Stavridis on whether the incidents suggest that Russia and China are taking advantage of a U.S. retreat from the world stage, saying that such an interpretation amounts to "trying to read domestic politics into international incidents."
"I don't see them connected to Trump and 'America First.' That's not what I'm seeing," Cancian said.
-- Richard Sisk can be reached at Richard.Sisk@Military.com.