Baby food produced by the German-based HiPP brand were pulled off the shelves in countries across Central Europe after rat poison was discovered in some jars over the weekend.

Five tampered jars have been recovered so far in Austria, the Czech Republic and Slovakia, but a sixth jar may "still be in circulation in Austria," said police in the German state of Bavaria, who are leading the investigation.

Later on Monday, the company and German police said the jars were deliberately tainted with rat poison as part of an ⁠attempt to extort their manufacturer.

Austria's health minister told parents, kindergartens and day care centers to use utmost caution when feeding young children HiPP. The company recalled some of its baby food jars in the three countries.

Authorities believe tampering occurred in 190-gram (6.7-ounce) jars of baby food made with carrots and potatoes for 5-month-old children that were sold at SPAR supermarkets in Austria. The first sample tested positive on Saturday.

On Monday, Austrian authorities said they were searching for a second jar of baby food that may have poison. It may have been sold at a SPAR supermarket in the eastern town of Eisenstadt, Austrian news agency APA reported.

"It is deeply disturbing that someone is apparently willing to endanger the health of babies for criminal motives," Health Minister Korinna Schumann told APA.

In the Czech Republic, two jars of HiPP baby food that tested positive for the poison were found in a store in the city of Brno. The state prosecution in Brno confirmed the find but did not give further details, citing a police investigation.

HiPP said its retail partners in Czechia and Slovakia "have already removed all jars of HiPP baby food from sale as a precaution."

Slovak police said they were investigating suspicious jars from a store in the city of Dunajska Streda.

Slovenia began preemptively withdrawing all HiPP products from shelves of Spar and other supermarkets, its health inspectorate said.

Austrian authorities also reached out to Hungarian officials, saying a poisoned jar may have been purchased by people living in the border region near Eisenstadt.

Burgenland Police in Austria said the suspicious products likely have a white sticker with a red circle on the bottom of the jar. Other warning signs include a damaged or opened lid and an unusual or spoiled smell. There might not be a popping noise when the jar is first opened.

"HiPP is the victim of an extortion attempt," the German company said in a statement later on Monday, saying the person trying to extort the company had sent it a message. It said the jars had been tampered with but did not mention poison.

"Ingolstadt police is conducting an investigation under the supervision of the Ingolstadt prosecutors' office into persons unknown on suspicion of attempted extortion against baby food producer HiPP," the police said in a statement shortly before HiPP's.

It did not provide specifics on ⁠the attempt but said all necessary measures were taken once an email by the presumed culprits came to light on April 16.

Austrian newspaper Die Presse reported on Monday, before the German police statement, that an email ​was sent to HiPP on March 27 and gave the company until April 2 to ​pay 2 million euros ($2.35 million) or two jars of baby food would be poisoned in each of three specific supermarkets in the Czech Republic, Slovakia and Austria.

Without ⁠providing dates, ‌HiPP said ‌the message it received was sent to "an unpersonalized collective address ⁠that, as part of our standard processes, is viewed ‌on occasions that are quite far apart", and that it had informed the authorities as soon as it became ​aware of it.

"This is a criminal, external manipulation beyond our control ⁠in three shops. We ​are not aware of any further instances of manipulation," it said.

The Burgenland public prosecutor’s office was investigating the case as "intentional endangerment of the public."

HiPP last week said the recall "is not due to any product or quality defect on our part. The jars left our HiPP facility in perfect condition."

HiPP said it was recalling all of its baby food jars sold at Austria's SPAR supermarkets – which include SPAR, EUROSPAR, INTERSPAR and Maximarkt stores – as a precaution.

Rat poison typically includes bromadiolone, which prevents blood from clotting, according to the Austrian Agency for Health and Food Safety. Ingesting rat poison could lead to bleeding gums and nosebleeds as well as bruising and blood in the stool.

Symptoms could appear two to five days after ingestion, the agency said.

In Prague, Ester Svetlik Danelova, who is currently on maternity leave, told The Associated Press (AP) that "the situation is worrying," for her family.

"I have three kids, and we definitely use this (baby food) throughout their lives," she said, adding that "on the bright side, it means I cook more at home now."