WASHINGTON (Reuters) - China hardliners in Congress are calling on the world's foremost semiconductor equipment makers - KLA, LAM, Applied Materials ( AMAT ), Tokyo Electron ( TOELF ) and ASML - to provide details of their sales to China.

Republican John Moolenaar and Democrat Raja Krishnamoorthi sent letters to the companies on Thursday, according to a Friday press release, amid pushback against expected U.S. rules that crack down further on tool shipments to China.

"We understand that some (toolmakers) believe we should limit the expansion of...future unilateral U.S. controls, due to perceived impacts on the competitiveness of this sector," the lawmakers wrote. "However, enhanced export controls simply are not mutually exclusive with a robust and thriving (toolmaking) industry," they added.

U.S. firms KLA, LAM, Applied Materials ( AMAT ), as well as Japan-based Tokyo Electron ( TOELF ) and Dutch ASML did not immediately respond to requests for comment.

But the letters come amid opposition even from Democrats to the Biden administration's long-delayed next round of export regulations, aimed at further stymying Beijing's access to toolmaking equipment.

Washington fears that progress in Chinese chipmaking capabilities, fueled by U.S., Dutch and Japanese equipment sales, is fueling the modernization of China's military.

But it has struggled to bring allies Japan and the Netherlands on board with another round of upcoming measures, leading U.S. industry to fear that U.S. companies will be unfairly harmed by them.

In an August letter, California Democrats argued that a further round of export controls "could send longstanding U.S. companies into a death spiral," because U.S. allies have not imposed similarly aggressive China export curbs on their own companies.