American forces downed its fourth unidentified object in just over a week, following the Chinese balloon that was first spotted crossing the US amid spy fears.
China’s Foreign Ministry has accused the US of “overreacting” and “seriously violating international practice” in shooting down the Chinese balloon.
Today the Philippines has accused China of shining a "military grade" laser light on its coast guard vessel and temporarily blinding some of its crew.
Meanwhile, on Sunday, maritime authorities in China’s Shandong province said they also spotted an “unidentified flying object” above waters and were “preparing to shoot it down."
So why has there been a flurry of flying objects in the US? Here is what we know so far.
What has happened so far?
In late January a giant Chinese balloon – which US officials have now said was a surveillance balloon – was spotted drifting through the sky.
From January 28 to February 4 it floated across 150 nuclear weapons silos at the Malmstrom Air Force Base, in Montana, and US Strategic Command, in Nebraska, which controls the country’s nuclear force.
It was eventually shot down off the South Carolina coast.
Less than a week later, US fighter jets downed another object off northern Alaska saying it was "within US sovereign airspace over US territorial water."
On Saturday, a US jet was instructed to down another “high-altitude airborne object” which was seen flying over Canada’s central Yukon Territory, around 100 miles from the US border, saying it posed a threat to a civilian flight.
The next day, President Joe Biden ordered US warplanes to down a fourth unidentified object over Lake Huron in Michigan “out of an abundance of caution".
What were the four objects?
The first spy balloon was "the size of three buses" and had a visible "technology bay", US media reported, including solar panels which were big enough to power several intelligence-gathering sensors.
But the US Department of State believes the object was part of a Chinese military fleet that has performed similar operations in 40 countries across five continents
Canada’s Defence Minister Anita Anand described the second craft as a “small, cylindrical object”.
Officials say they are around the same size as a Volkswagen Beetle but “slightly different in profile”, according to The Washington Post.
But defence officials have declined to properly identify what the three objects are. This has raised questions over the threat the objects could have represented to civilians.
"We’re calling this an object because that’s the best description we have right now. We do not know who owns it, whether it’s state-owned or corporate-owned or privately owned," White House National Security Council spokesperson John Kirby said.
And Deputy Pentagon press secretary Sabrina Singh said: "These objects shot down on Friday and Saturday were objects and did not closely resemble the [People’s Republic of China] balloon.
"When we can recover the debris, we will have more for you.”
Is China spying?
Only the first object so far has been attributed to Beijing and Pentagon press secretary Brigadier General Patrick Ryder said that the latest incident is “part of a larger Chinese surveillance balloon programme”.
But Alexander Neill, an analyst at Hawaii’s Pacific Forum think tank, said the balloon's intelligence gathering was likely limited, suggesting it could have been political games instead.
"China has its own constellation of spy and military satellites that are far more important and effective in terms of watching the US, so I think it is a fair assumption that the intelligence gain is not huge," Mr Neill told The Telegraph.
US military officials have not disclosed whether they believe the three latest objects came from China, whether they have posed any threats to US radar or military sites, or how fast they were travelling.
China has continued to claim that the balloon was merely a weather research "airship" that had been blown off course and they were not happy it was shot down.
There has been no Chinese reaction to the latest downings.
Why has there been a flurry of items?
The balloon was spotted just days before Antony Blinken, the US secretary of state, was set to visit China and he swiftly cancelled his trip.
Some analysts say it may be the start of a major Chinese surveillance effort targeting foreign military capabilities ahead of possible acute tensions over Taiwan in coming years.
Officials have said three balloons are now known to have briefly overflown US territory during Donald Trump’s administration – which went undetected at the time.
And what about extraterrestrial life?
The US has said they cannot rule out that the objects were extra-terrestrial, but after these remarks, a defence official who requested anonymity said that there is “no indication of aliens or extraterrestrial activity with these recent takedowns”.
How has the US responded?
US President Joe Biden is yet to respond to the developments, sparking concern among his colleagues. One Democratic congressman told CNN that the silence from Biden was “odd” – particularly given that “people are freaked out”.
Senator Michael Bennet, a Colorado Democrat, also said in a statement that he is looking forward to hearing more from the administration about the situation.
He said: "The American people deserve timely answers about the objects that were shot down over Lake Huron, Alaska, and Canada this weekend.
"We need to understand the nature of the threat to our national security. As a member of the Senate Intelligence Committee, I expect to be briefed on these incidents early this week.”
It has been reported that Biden's team has cautioned against a public address until much more is concretely known about what has happened.
Canada’s Defence Minister Anita Anand said: “To our knowledge, this is the first instance of Norad downing an object in Canadian airspace, and the importance of this moment should not be underestimated."
Democratic Senator Jon Tester told CBS: "What's gone on the last two weeks or so... has been nothing short of craziness. And the military needs to have the plan to not only determine what's out there but determine the dangers."
Republicans have repeatedly criticised the Biden administration for its handling of the first suspected spy balloon, saying it should have been shot down far sooner.
