Dennis Hastert, the speaker of the US House of Representatives, rejected calls for his resignation over his handling of a congressional sex scandal on Thursday as the ethics committee issued four dozen subpoenas to House members and aides to discover who was aware of suggestive e-mails sent to under-age pages by former representative Mark Foley.

Mr Hastert defiantly said he would not step down as speaker. He defended the Republican leadership against criticism it had been slow to investigate complaints against Mr Foley, noting they had dealt with it “immediately” after becoming aware of more explicit instant messages.