BOSTON (CBS) — Have you received seeds in the mail that you didn’t order? Don’t plant them, the government says.

The USDA said Tuesday that it “is aware that people across the country have received suspicious, unsolicited packages of seed that appear to be coming from China.”

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The agency is asking anyone who received the seed packages to contact their state plant regulatory official and wait for further instructions.

“Do not plant seeds from unknown origins,” the USDA said.

The Massachusetts Department of Agricultural Resources put out its own notice Tuesday afternoon, saying that “several” Massachusetts residents have received the unmarked, unsolicited seeds.

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“While the exact types of seeds in the packages are unknown, the seeds are thought to be invasive plant species, and not believed to be harmful to humans or pets but could pose a significant risk to agriculture or the environment,” the department said.

Residents with the seeds are asked to fill out an online form and hold on to them and all packaging, including the mailing label, until they get further instructions.

The USDA said it’s working with the Department of Homeland Security to investigate and test the seeds. Right now, they don’t have any evidence indicating that the shipments are anything more than a “brushing scam” from a company trying to boost sales by sending unsolicited items and posting false customer reviews.

Agriculture officials in multiple states have now warned against planting the seeds.

“If you think of a plant like Kudzu, which is down in the South and is taking over the whole South, these are invasive vines that strangle out native species, trees, and plants and can cause some serious damage,” said Mark Saidnawey of Pemberton Garden Services in Cambridge.

“Don’t flush them down the toilet, don’t put them in the trash. They can still germinate through those channels,” he added.

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Jerry Ensminger is an avid gardener but the recent delivery of a package of seeds made him suspicious. “I looked at the label on it and it was from a Chinese post office,” he said. “They might be completely harmless seeds but I’m not going to risk it. No one should risk it.”