The US believes that the flying objects shot down over North American airspace on Friday and Saturday were balloons, according to Senate Majority Leader Chuck Schumer.
Washington has been on high alert since its military destroyed a suspected Chinese spy balloon earlier this month.
While he didn't say specifically that the two latest objects were Chinese, Mr Schumer told ABC on Sunday that Beijing was likely using a "crew of balloons" that had "probably been all over the world".
Canadian Prime Minister Justin Trudeau confirmed that the latest object was shot down on Saturday over the Yukon in north-west Canada.
Both Canadian and US aircraft were scrambled to track down the object, which Mr Trudeau said has "violated Canadian airspace". It was taken out by a US F-22 fighter jet.
Speaking on Sunday, Mr Trudeau said recovery teams were on the ground trying to find the object and that there was still "much to know".
Mr Schumer, meanwhile, implied that suspected surveillance balloons had been in operation for years and that Congress should examine why it took so long for the US to find out about them.
"The bottom line is, until a few months ago we didn't know of these balloons - our intelligence and our military didn't know," he said.
Mr Schumer, who said he had been briefed by national security adviser Jake Sullivan, said the two latest objects were smaller than the first balloon.
Asked whether China would have to shut down any surveillance programme using balloons, he said Beijing had been "humiliated".
"I think the Chinese were caught lying, and it's a real step back for them… they look really bad," he said.
"They're not just doing the United States, this is a crew of balloons... they've probably been all over the world," he added. China has yet to respond to Mr Schumer's comments.
Three objects have been shot down over North America in total in the past week.
The American military destroyed a Chinese balloon on 4 February and on Friday an object the size of a small car was shot down off Alaska.
China has denied the balloon - which first entered US airspace on 28 January - was used for spying purposes, saying it was a weather device gone astray.
The latest object was flying over central Yukon at about 40,000 ft (12,000m) and was intercepted at about 15:41 local time on Saturday, defence minister Anita Anand told reporters.
She described it as "small" and "cylindrical".
MsAnand said it was taken out "about 100 miles" from the US border, adding it posed a "reasonable threat to civil aviation".
She said it "appears to be smaller than the one shot down off the coast of South Carolina" last Saturday - meaning the giant Chinese suspected spy balloon that measured 200ft (60m) tall.
Posting earlier on Twitter, Prime Minister Trudeau thanked the North American Aerospace Defense Command (NORAD), which carries out air defence for the US and Canada and led the mission.
The White House said the object had been tracked and monitored "over the last 24 hours".
"Out of an abundance of caution and at the recommendation of their militaries, President Biden and Prime Minister Trudeau authorised it to be taken down," it said.
"The leaders discussed the importance of recovering the object in order to determine more details on its purpose or origin."
Giving more details on the mission to take down the object, the US Department of Defense confirmed two F-22 jets took off from a military base in Anchorage, Alaska and the object was shot down with an AIM 9X missile.
Pentagon Press Secretary Brig Gen Pat Ryder added that the FBI will be "working closely" with Canadian police.
Separately on Saturday, the US military also scrambled fighter jets over Montana as some airspace was closed - but it turned out to be a "radar anomaly" and nothing unusual was found.
In a short statement, the military said US troops, including from the Alaska National Guard, were still conducting search and recovery activities on sea ice for Friday's object.
It said at the time that it had no further details about the object's capabilities, purpose or origin but confirmed the FBI is helping with the recovery near the Alaskan town of Deadhorse.
"Arctic weather conditions, including wind chill, snow, and limited daylight, are a factor in this operation, and personnel will adjust recovery operations to maintain safety," it added - and that the rescue operation will continue as weather permits.
Last weekend, defence officials told US media that debris from the Chinese balloon landed in 47ft (14m) of water - shallower than they had expected - near Myrtle Beach, South Carolina.
China has denied the balloon - which first entered US airspace on 28 January - was used for spying purposes, saying it was a weather device gone astray.
The US, however, said the balloon is part of a fleet of surveillance balloons that have flown over five continents.
The balloon incident has strained US-China relations, with Secretary of State Antony Blinken cancelling a planned trip to Beijing.
Chinese officials on Friday accused the US of "political manipulation and hype".
In an interview on Thursday, President Biden defended his handling of the Chinese balloon, maintaining that it was not "a major breach".
