Henry Clifford, the 83-year old American who spent US$25,000 of his own money to place advertisements at New York train stations that showed maps of Israel's gradual expropriation of Palestinian lands over 64 years, says he is unfazed by criticism from pro-Israeli groups and will continue to take out similar placements.

"I already have running this week in a local newspaper here in Connecticut the same ad and I am looking into running the same ad in the Boston area railroad stations," Clifford, who is the chairman of the Committee for Peace in Israel and Palestine, said in a telephone interview with Arabian Business from his home in Connecticut.

Clifford, who has lived and worked in the New York area all of his professional career, took out ads on platforms at Metro-North railroad stops this month that read "4.7m Palestinians are classified by the UN as refugees". The billboard includes maps showing the loss of Palestinian land from 1946-2010 to Israel.

The ads stirred up a storm in New York with Jewish organisations, including the pro-Israel Anti-Defamation League calling the signs "deliberately misleading and biased" and "inflammatory".

MTA, which manages transport in New York City, said it does not accept or reject a proposed ad, based on the viewpoint that it expresses or because the ad might be controversial, and Clifford is unmoved by the criticism.

"It's completely expected, I'm not surprised that organisations like that would have something to say along the lines of what they said," Clifford said.

"It's ironic that one of those organisations accused me of placing inflammatory ads. The word inflammatory is inflammatory," he added. "They're accusing me of wrongdoing - of trying to inflame something when the fact is their response is more inflammatory than my ads. I don't see how maps that present historical and geographical facts can be called inflammatory or anti-Semitic, or misleading. They are the facts and if you notice we don't editorialise. We present the facts and we let people decide for themselves what the conclusion is we don't tell them what to think, we just say here are the facts you decide."

Clifford has received over 600 emails from all over the world in response to the billboards, which have been reported on by television and radio stations, newspapers, and picked up by blogs and posted on social media sites like Facebook.

"I am astonished at the news coverage [and] the responses and I am immensely pleased that this has happened," Clifford said, adding "The purpose of these ads is to inform people, the news coverage has helped me accomplish my goal."

"We have been doing a great deal of many things over the years and I must say without a great deal of success and this has been an absolute astonishment to me because of the news coverage," Clifford said. "The internet is a simply amazing tool for getting the word around. It's absolutely amazing what has happened here."

Pro-Israeli organisations aside, the feedback has mostly been positive.

"My experience in this matter over the years has been that the response would very often be very critical and in fact often be nasty, profane, angry. In this case I would judge that 95 percent of the emails received have been positive and 5 percent negative. Among the 5 percent only a few have been nasty. That's another surprise. I fully expected many more critical responses."

Clifford said he's also surprised that he hasn't been contacted by Palestinian government officials .

Though he's received emails from people offering contribute financially to his activities, Clifford said there are no plans to open a fund that would finance his undertakings.

"My response so far has been that their contribution can be to take this ad and use it locally in any way that they want, put in newspaper, a railroad station or anywhere that they think is suitable and fund that effort themselves rather than give the money to me," he said. "If I continue this on a very large scale then yes perhaps I would want to open an avenue for contributions."

Click here to watch the video