High prices are driving an increase in attempts to bring eggs into the US from Mexico, according to border officials.

Officers at the San Diego Customs and Border Protection Office have seen an increase in the number of attempts to move eggs across the US-Mexico border, according to a tweet from director of field operations Jennifer De La O.

“The San Diego Field Office has recently noticed an increase in the number of eggs intercepted at our ports of entry,” wrote De La O in the Tuesday tweet. “As a reminder, uncooked eggs are prohibited entry from Mexico into the U.S. Failure to declare agriculture items can result in penalties of up to $10,000.”

Bringing uncooked eggs from Mexico into the US is illegal because of the risk of bird flu and Newcastle disease, a contagious virus that affects birds, according to Customs and Border Protection.

In a statement emailed to CNN, Customs and Border Protection public affairs specialist Gerrelaine Alcordo attributed the rise in attempted egg smuggling to the spiking cost of eggs in the US. A massive outbreak of deadly avian flu among American chicken flocks has caused egg prices to skyrocket, climbing 11.1% from November to December and 59.9% annually, according to the Bureau of Labor Statistics.

The increase has been reported at the Tijuana-San Diego crossing as well as “other southwest border locations,” Alcordo said.

For the most part, travelers bringing eggs have declared the eggs while crossing the border. “When that happens the person can abandon the product without consequence,” said Alcordo. “CBP agriculture specialists will collect and then then destroy the eggs (and other prohibited food/ag products) as is the routine course of action.”

In a few incidents, travelers did not declare their eggs and the products were discovered during inspection. In those cases, the eggs were seized and the travelers received a $300 penalties, Alcordo explained.

“Penalties can be higher for repeat offenders or commercial size imports,” he added.

Alcordo emphasized the importance of declaring all food and agricultural products when traveling.

“While many items may be permissible, it’s best to declare them to avoid possible fines and penalties if they are deemed prohibited,” he said. “If they are declared and deemed prohibited, they can be abandoned without consequence. If they are undeclared and then discovered during an exam the traveler will be subject to penalties.”