A US supplier of voting machines has agreed to a probe into its takeover, saying it will dispel "baseless" allegations about ties to Venezuela.
President Chavez has no links to Smartmatic, the firm says
Smartmatic, which bought Seqouia Voting Systems in 2005, and Caracas strongly deny media suggestions that President Hugo Chavez has any role in the firm.
Seqouia's machines are being used in 17 states in the November mid-term polls.
The inquiry comes amid growing concerns about the reliability of electronic voting machines in general.
Touch-screen voting is in place in 33 states, with many experts warning that the machines are easy to tamper with.
Based in the state of Florida, the software firm Smartmatic is owned primarily by three Venezuelans.
It was hired by the Venezuelan government - which has strained relations with Washington - to provide election machines ahead of the recall referendum on Mr Chavez's rule in 2004.
A year later, the company bought Sequoia, a US company that has been providing voting machines since the 1980s.
In May 2006, Representative Carolyn Maloney, a Democrat, asked the federal authorities to look into the takeover.
This weekend, US press reports suggested the Committee on Foreign Investment (CFIUS) had launched a formal investigation into the acquisition.
Sequoia and Smartmatic say they voluntarily submitted to a federal review.
"No foreign government or entity - including Venezuela - has ever held an ownership stake in Smartmatic, and we have voluntarily filed with CFIUS to put to rest the baseless but persistent rumours about our ownership," the firm's chief executive, Antonio Mugica, said in a statement.
He added: "We are confident it will clear the air so we can focus on what we do best."