Several trucks involved in the "People's Convoy" – the American answer to Canada's "Freedom Convoy" – were involved in a crash on their way to protest in Washington DC.
The drivers are largely right-wing critics of the Joe Biden administration who oppose vaccine mandates.
State troopers in Oklahoma had to shut down the Will Rogers Turnpike for a half an hour on Sunday after two semis and two pickup trucks were involved in a crash, according to ABC 8.
The incident happened around 5.30pm. Troops confirmed there were injuries but would not provide further detail.
The trucks left Adelanto, California last week and plan to arrive just outside Washington DC on 5 March. From there, the convoy organisers say the trucks will drive on the Beltway to demand Mr Biden rescind the national emergency enacted at the start of the pandemic. Mr Biden has extended the state of emergency to beyond 1 March, the original date it was planned to end.
The convoy organisers said the the truckers will not enter central Washington DC, though some participants – like Pennsylvania trucker Bob Bulos – have said they want to shut down the Beltway as part of their protest.
Convoy organisers said they have no intention of breaking any laws during their protest or fighting with police.
The convoy has already raised more than $1.5m in donations. That money will go toward fuel costs for the truckers, which will inevitably begin to increase as the war between Russia and Ukraine continues.
The protest comes at a time when many states are beginning to roll back their coronavirus emergency policies – like mandatory indoor masking – as coronavirus cases begin return to their pre-Omicron variant levels.
The convoy began with about 50 pickup trucks and around two dozen semis, but has grown as it has traveled towards Washington DC to about 100 vehicles. The convoy spans a distance of about 80 miles, according to organisers.
Other convoys are leaving from different parts of the US to merge with the California convoy when it reaches Washington DC on Saturday.
Another group, the Freedom Convoy USA, was asked to disband its protest and combine with the People's Convoy after it reached Las Vegas with only five vehicles. It had planned to arrive in Washington DC on 1 March to be present for Mr Biden's State of the Union address.
Despite the assurances from the organisers that the truckers won't be entering central Washington DC, federal agents are building fences around the US Capitol to prevent any potential 6 January style events from occurring during the protest or Mr Biden's speech.
The Pentagon has also deployed 700 unarmed National Guardsmen to Washington DC to deal with traffic issues that may arise from the trucker protest should it enter the city.
