Russian MP3 site Allofmp3.com says legal action by US record firms to shut it down is "unjustified".
Allofmp3.com has more than 300,000 tracks
In a statement on its website the firm repeated assertions that its service was legal under Russian law.
Allofmp3.com sells songs at a fraction of the cost of downloads from services such as iTunes and Napster.
The company says it pays royalties to a Russian licensing body, but record firms say it is not authorised to accept payments.
The statement said: "An attempt by the major record labels to use a US court to as part of its campaign against Allofmp3.com is imprudent."
The firm said the suit was "unjustified as Allofmp3.com does not operate in New York".
It continued: "Certainly the labels are free to file any suit they wish, despite knowing full well that Allofmp3.com operates legally in Russia."
The lawsuit was filed in New York earlier this month on behalf of Arista Records, Warner Bros, Capitol and UMG recordings.
They are suing Moscow-based Mediaservices, which runs Allofmp3.com and another music site, allTunes.com.
The record labels say the sites are selling songs without permission.
Allofmp3.com sells albums for about $1 (60p) and charges only a few cents for songs. By contrast, the world's most popular music download service, iTunes, charges $10 (£6) for an album.
The website is already facing legal action from the British Phonographic Industry, on behalf of UK record labels.