China has reportedly unblocked a certain search term in recent days: “third-generation pig.” The phrase apparently refers to autocratic North Korean leader Kim Jong Un, and the decision to unblock it could indicate growing tensions between Beijing and Pyongyang over Kim’s recent nuclear and missile tests.

In the past, when the moniker was searched on Baidu, China’s largest search engine, viewers were directed to a message that said it did not conform to filter regulations. But as of Wednesday, the term was being widely searched, Korea Times reported Friday.

Tensions have recently simmered between the two allies, as some have questioned the sustainability of their strategic relationship. Following an underground nuclear test, China called on Pyongyang to “fulfill its promise of denuclearization and stop any actions that would worsen the situation.” The tests have prompted the U.S. to propose some of the harshest sanctions ever against the country. The approval last week of a sanctions rough draft in the U.N. Security Council was viewed by some as an indication that China has been increasingly disgruntled with North Korea.

“We’ve seen how the latest U.N. resolution reflects China’s anger at its troublesome ally,” Bruce Klingner, senior research fellow in Korean and Japanese affairs at the Heritage Foundation, a conservative Washington think tank, recently told International Business Times. 

China was expected to increase security along its border to prevent smuggled technology that could aid the missile program. Sanctions on commerce could also damage the relations between the two allies, potentially requiring all cargo in and out of the East Asian nation be inspected. Another sanction could ban some of the country’s major exports, including coal, iron, gold, titanium and rare earth minerals.

Kim’s autocratic government is considered among the world’s most oppressive and corrupt regimes in the world. Freedom of speech, press and religion are virtually nonexistent in the hermit kingdom. The government is believed to maintain secret labor camps where government opponents face torture and starvation.