Busloads of buses and cargo of planes, National Guard troops poured into the nation’s capital on Saturday, as governors responded to US defense officials’ urgent requests for more troops to help guard Washington even as they watched anxiously at possible violent protests in their own states.

Military leaders spent most of the night Thursday and Friday calling on the state in an unprecedented call for more National Guard troops to help lock down large swathes of the city in the days before President-elect Joe Biden’s inauguration. In the dribs and drabs, the governor replied, some agreeing to send an extra dozen, 100 or even 1,000, while others said no.

The calls reflect concerns that violent extremist groups are targeting the city after a deadly uprising on the US Capitol on January 6.

Threats range from armed insurgents to possible attempts to plant explosive devices on so-called soft targets. But as Washington begins to resemble an armed camp, with more than 25,000 guards set to be in the city as early as next week, concerns about violence in the state capital have mounted.

Oregon Governor Kate Brown said she rejected a federal request to send at least 100 more National Guard troops to DC “I don’t think we can safely fulfill that commitment,” Brown said. Oregon has agreed to send 30 to Washington, but state leaders are concerned about violence at the state capitol in Salem.

Others agreed, sparking dizzying bursts of military and convoy flights into the region.

“The peaceful transfer of power is a central principle of American democracy, and Connecticut stands ready to help protect our country.” said Connecticut Governor Ned Lamont, who initially agreed to send 100 guards and on Friday agreed to send 200 more.

In all, more than 130 US Air Guard flights in the past 72 hours have brought at least 7,000 Guard troops to Joint Base Andrews in Maryland, according to US officials, who spoke on condition of anonymity to discuss internal numbers. Thousands more were in buses and military trucks, rumbling down the highway to Washington.

Army General Dan Hokanson, head of the National Guard Bureau, called in general aides across the country, and others, such as Army Secretary Ryan McCarthy, called in governors for help. McCarthy praised the state, saying defense and military officials were well aware of the threats they also faced.

“The governors and TAG were great. They helped us a lot,” McCarthy told The Associated Press.

“That’s the problem – that in the midst of a very dire situation you see how great this country is, everyone is getting together and helping each other get through this.”

What began in early January as a routine deployment of some 350 DC National Guard members to aid protests that are expected to explode over the past two weeks became a much larger operation to protect the inauguration and the US Congress Building, and to block access to the city and its many historical monuments.

When the protesters entered the Capitol on January 6, only a little over 100 National Guards were scattered around the city, guarding the Metro’s checkpoints and entrances. Hours later, five people are dead, the Capitol is in disarray and 1100 DC Guards have been activated.

The next day, as information arrived about more planned violence, requests went out for 6,200 members of the Guard from surrounding states.

On Thursday evening, as law enforcement and defense officials flooded maps and conducted security drills, they concluded they needed at least 25,000 to lock down Capitol grounds and vast areas of DC, including the National Mall. And they agreed that most of the Guards would be armed.

At that time, a new chapter of summons to state governors and military leaders began.

Many governors were willing to help, but they made it clear that the state capital was their priority. Some agreed to send more, while others couldn’t. And the numbers vary widely.

Pennsylvania Governor Tom Wolf doubled his initial commitment from 1,000 to 2,000. Other states managed to collect an additional dozen.

After reviewing threats against its own country, Minnesota decided it could significantly increase its contribution and would send 850 guards rather than the 130 originally deployed to leave, according to the state’s aide general, Major General Shawn Manke.

Ohio Governor Mike DeWine has agreed to send 700. On Friday, he announced he would send 300 more – even as he ordered nearly 600 to secure the Ohio state home in Columbus. So it is with the Governor of North Carolina.

Roy Cooper initially agreed to send 200 guards, and on Friday a Ford Porter spokesman said the country would send 100 more. Iowa first said it sent 250 and now the number is 265.

The big military response comes as Congress and law enforcement authorities try to figure out how the US Capitol captured the dramatic power of January 6.

The leaders of four committees in the Democratic-controlled House sent a letter on Saturday seeking briefings and documents from the FBI and other federal agencies as part of their review of the insurgency.

The call for more American soldiers also underscores the Pentagon’s limits on the use of active duty troops. Under the law, they cannot be used for law enforcement, and officials intend to avoid the emergence of armed active forces being used against US citizens on American soil.

Active duty forces routinely prepare to respond to emergencies in Washington, such as flight violations in restricted airspace over DC, and rapid reaction forces are on standby. Other active duty units will take part in various inauguration ceremonies.