A pregnant woman and her unborn child were killed in a wrong-way crash on the eastbound Long Island Expressway service road on the North Hills-New Hyde Park border Sunday afternoon, sources said.

The woman was about six months pregnant, a source said.

Nassau police would not confirm the woman’s death, but said four people were injured in the crash. It was unclear which vehicles they were in or the extent of their injuries.

The crash occurred at 3:37 p.m. on the South Service Road between Exits 34 and 35, police said.

Nassau police were on the scene for hours, with the service road closed between New Hyde Park Road and Shelter Rock Road.

The circumstances of the crash were not immediately clear.

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Det. Lt. Richard LeBrun, the department’s top spokesman, on Sunday declined to release any details on the crash, but said the investigation is ongoing.

After the crash, dozens of residents from two nearby condominium developments gathered in a business’ parking lot because the road closure prevented them from reaching their homes.

“We’ve been here for two hours already,” said Amy Chin, 34, who was on her way home with her husband, two young daughters and other family members from a Father’s Day outing.