A handful of Senate Democrats have split with President Obama's controversial birth-control mandate and slammed the administration's requirement that church-affiliated employers cover contraceptives.

The five Democrats in the Senate expressing concern about some parts of the administration's policy include, most recently, Sens. Ben Nelson of Nebraska and Bill Nelson of Florida, who have spoken publicly about their unhappiness with the mandate.

"This was a bone-headed decision by HHS," Sen. Ben Nelson said of the new Health and Human Services mandates, according to the Nebraska Radio Network.

Nelson agreed with state Attorney General Job Bruning's decision to file a legal challenge to the mandate.

Florida's Nelson has also raised concerns. "My position is that church-affiliated organizations should be exempt, not just churches," Nelson told the Tampa Bay Times Buzz Blog, adding that he has called the White House to express his concerns.

"It's a matter of religious freedom," Nelson spokesman Dan McLaughlin told ABC News.

The senators' statements follow other Democratic senators who voiced concerns this week.

Sen. Joe Lieberman, the independent from Connecticut who caucuses with Democrats, tweeted Wednesday, "I am opposed to the Administration's new requirement that religious org.'s must offer employees contraception benefits."

Democratic Sen. Bob Casey of Pennsylvania wrote a letter to President Obama last week calling on him to reverse the new ruling.  "I have strongly supported efforts to provide greater access to contraception," Casey wrote. "I believe, just as strongly, that religiously affiliated organizations like hospitals and universities should not be compelled by our Federal government to purchase insurance policies that violate their religious and moral convictions."

Meanwhile, West Virginia Democratic Sen. Joe Manchin, up for re-election,  has teamed with Republican Sen. Marco Rubio of Florida on legislation that would repeal the administration's mandate.

In a letter sent to Obama last week, Manchin called the mandate "a direct affront to the religious freedoms protected under the First Amendment of our Constitution."

Likewise, Republicans have called for the same thing en masse, coming out strong in a coordinated fashion this week in the House of Representatives and the Senate, demanding that the president change his position.

"The Obama administration's decision to force religious hospitals, charities and schools to comply with the mandate that violates their religious views is abhorrent to the foundational principles of our nation," Senate Minority Leader Mitch McConnell, R-Kentucky, said on the chamber floor this week. "This is a huge mistake that I hope the administration is currently reconsidering. And if they don't, Congress will act."