Modi'in Mayor Haim Bibas threatened on Tuesday to bar ultra-Orthodox visitors from his city's central park in response to Modi'in Ilit Mayor Yaakov Gutterman's pledge to keep non-Haredi visitors out of an archaeological site slated to open soon in his town.

The site, called Khirbet Bad-Issa, is a Second Temple farming village and was proclaimed a national heritage site by the government in 2011.

Last week Gutterman told the Haredi newspaper Yated Neeman that the archaelogical site "will be open only to the ultra-Orthodox public, which will keep it a proper place for them to visit and connect to their Jewish roots, without the distortions and disruptions of other places, where there is fear of hearing false opinions."

"National heritage sites are places central to the history of the Jewish people and should be open to everyone, whatever their world view or religious affiliation may be," Bibas wrote in a letter sent to Gutterman yesterday.

"As you knowm, two years ago, we inaugurated the Anabe Park in Modi'in - the city's central park. Since it opened, thousands of Modi'in Ilit-Kiryat Sefer residents have visited it, since your city doesn't provide adequate family recreation facilities. Up to now, I have refrained from discriminating between ultra-Orthodox and secular visitors, despite the multitude of petitions by Modi'in residents complaining that the park is being taken from them."

Bibas ended his letter with a threat: "If the municipality you head doesn't reverse its decision and will in fact bar secular visitors (from the archaeological site ), the city of Modi'in will bar residents of your municipality entrance to Anabe Park."

Only a few kilometers divide the mixed secular-religious city of Modi'in, which straddles the Green Line, from the Haredi West Bank settlement of Modi'in Ilit.

The government has invested NIS 3 million in the archaeological site, which was uncovered in 1994. At first, the Haredi residents of the town accused archaeologists of desecrating tombs and even stoned and cursed the site supervisor. But the work, conducted by the archaeological department of the Civil Administration, continued and eventually led to the discovery of a partially preserved synagogue, as well as streets, a wine press, a ritual bath, public buildings and a 145 Roman coins from the first century B.C.E.

Yated Neeman also quoted Gutterman as saying that "the government decision stated that the Haredi public would determine the character of the site, and all the themes and historical data would be based on [religious] sources."

Gutterman refused to respond to Haaretz's questions on the matter.