Christian groups are among perceived conservatives complaining of being targeted by the Internal Revenue Service, the government agency responsible for tax collection in the United States.

President Barack Obama pledged that IRS employees who discriminated against groups such as the Tea Party will be held to account after an independent regulator strongly criticised the tax organisation for "inappropriate" behaviour.

The IRS apologized last week for the actions of low level staffers in its Cincinnati, Ohio branch, who were harassing groups they believed were affiliated with conservative politics.

Groups with the name "tea party" or "patriot" in their names were among those singled out by IRS staffers.

The groups targeted were seeking tax exempt status as charitable or social welfare organizations under U.S. laws.

The admission by the IRS has grown into a full-blown scandal in Washington, as more and more reports are revealing that such efforts by its employees extended beyond the Cincinnati bureau.

Among those complaining is Franklin Graham, the son of evangelist Billy Graham.

The younger Graham, who has inherited his father's post running the Billy Graham Evangelist Association and runs his own charity called Samaritan's Purse, expressed his concerns in a letter to President Barack Obama.

Graham said the IRS notified both organizations last September that they were reviewing their activities for the year 2010.

In the letter, the contents which were given to the Politico webzine, Graham said he now believes the IRS was being used by someone in the Obama administration to intimidate the Graham organizations.

He wrote that he thought the efforts by the IRS were punishment for a message put out by the Billy Graham Evangelistic Association.

That message urged voters to back "candidates who base their decisions on biblical principles and support the nation of Israel."

The IRS visited the North Carolina offices of both groups to conduct a tax audit.

"While these audits not only wasted taxpayer money, they wasted money contributed by donors for ministry purposes as we had to as we had to use precious resources servicing the IRS agents in our office," said Graham.

H said that because of the recent revelations of IRS actions targeting conservative groups, he does not believe the auditing of his organizations were a coincidence or justifiable.

Graham called the alleged attempts at intimidation "morally wrong and unethical".

World News Net Daily (WND) reported another alleged instance where a Christian group was targeted by the IRS.

Cherish Ministries, a group organized to coordinate pro-life efforts among churches, told WND it was harassed by an IRS agent who claimed they had to provide their audience with both pro-life and pro-choice educational material.

The group was also accused of being a political organization, even though its application noted that it spend less than five percent of its time on political activities.

Peter Shinn, the founder of Cherish Ministries, also said the IRS rewrote the group's bylaws to make them appear to be politically oriented.

The Thomas More Society, an advocacy law firm, has accused the IRS of harassing two other faith-based pro-life groups who they represented, according to the Illinois Review.

Another group, Coalition for Life of Iowa sought tax exempt status in 2009.

The IRS sought information regarding the content of prayers made at a facility of the pro-choice group Planned Parenthood.

It also demanded that Coalition for Life members not perform activities that could be interpreted as picketing or protesting by police and to refrain from any actions which could be seen as attempts to harass abortion-seeking clients.

The IRS backed off when the Thomas More Society made a legal challenge.

The legal group also has represented a pro-life group called Christian Voices for Life.

The IRS sent a letter to the group demanding to know if they educated people on both sides of the abortion issue and whether or not they blocked or talked to people who were entering medical clinics.

The Thomas More Society sent a letter to the IRS indicating it was violating the rights of Christian Voices for Life under the U.S. Constitution.