Campaigners in favour of tightening US immigration laws are preparing to set off on a 12-city tour to try to build support for their cause.
The Minuteman Project, which patrols the US-Mexico border, is launching the 10-day convoy after pro-immigrant mass rallies across the country.
About 100 people will travel from Los Angeles to Washington DC for a rally.
It comes as the US Senate prepares to try again to break the deadlock on immigration reform.
The Minuteman group is made up of volunteers who strongly oppose illegal immigration, and organise border patrols to try to prevent people crossing into the US illegally.
It says it will use the caravan to mobilise voters and recruit members, and try to counter the impact made by the huge pro-immigrant rallies held earlier this week.
The caravan will leave Los Angeles on Wednesday, where it plans to highlight unemployment in the African-American community.
It says the problem is caused by illegal immigrants taking jobs "that Americans would be willing to do".
The group is planning to hold rallies in cities including Phoenix in Arizona, and Crawford in Texas, where President George W Bush has a ranch.
The convoy will finish by driving to Capitol Hill in Washington DC for a rally on 12 May.
"Our power is not putting a million people on the street, our power is putting 10 million people at the voting box," said executive director Stephen Eichler.
The US Senate's majority leader, Bill Frist, said on Tuesday the Senate would try again within weeks to break the deadlock on immigration reform.
He was speaking after huge demonstrations on Monday illustrated immigrants' demands for recognition.
Congress is caught between competing bills that would either criminalise or legitimise illegal immigrants.
Mr Frist said his attempts at reconciliation would focus on "border security first and foremost".
But he acknowledged that legislation also had to address the issue fo the estimated 11.5 million illegal immigrants in the US.
