ABC News' Teddy Davis and Rigel Anderson report: Embattled Republican Sen. Susan Collins is calling on Sen. John McCain to stop paying for automated phone calls which describe Sen. Barack Obama as having "worked closely" with "domestic terrorist Bill Ayers."

"These kind of tactics have no place in Maine politics," said Collins spokesman Kevin Kelley. "Sen. Collins urges the McCain campaign to stop these calls immediately."

Contacted on Friday by ABC News, the McCain campaign would not say if it was going to heed the request of Collins who serves as his campaign's co-chair in Maine.

"Obviously, Sen. McCain has great respect for Sen. Collins. But beyond that," said McCain spokesman Brian Rogers, "we don't have any comment."