At a news conference at the Capitol, Hastert read a prepared statement and did not answer questions shouted at him by reporters.
Foley resigned his seat Friday. The first communications made public last week were 2005 e-mails that were inappropriately friendly between an adult and a teenage boy but not specifically sexual, the Washington Post said. But ABC published what Hastert called "vile and repulsive" instant messages sent by Foley in 2003.
Also Monday, several prominent conservatives called for Hastert's resignation, the conservative newsweekly Human Events reported. They included David Bossie, president of Citizens United, and Michael Reagan, a son of former President Ronald Reagan and a conservative columnist.
"Any member of Congress who was aware of the sexual e-mails and protected the congressman should also resign effective immediately," Reagan said. "I was sexually abused by a day camp counselor at age 8 and also made to be part of child pornography."