South Korea denounced North Korea on Monday for a sexist swipe at President Park Geun-hye, in the latest verbal tit-for-tat between the rival Koreas amid lingering tensions over Pyongyang’s possible nuclear test.

Unification Ministry spokesman Kim Eui-do said the North used vulgar expletives toward Park, calling the North’s latest slander immoral.

Kim’s comments came a day after North Korea’s Committee for the Peaceful Reunification of Korea called her “a wicked sycophant and traitor, a dirty comfort woman for the U.S. and despicable prostitute selling off the nation.”

South and North Korea accused each other of violating their February agreement to halt smear campaigns against each other.

The North Korean committee, which handles inter-Korean affairs, issued the English-language statement in response to Park’s summit talks last week with U.S. President Barack Obama in Seoul.

In a joint news conference with Obama, Park warned Pyongyang that a new form of provocation would lead to new levels of pressure from the international community. Obama also told Pyongyang that “Threats will get North Korea nothing, other than greater isolation.”

The warnings came amid indications that North Korea is fully prepared to conduct another nuclear test. North Korea conducted nuclear tests in 2006, 2009 and February 2013, drawing international condemnation and tightened U.N. sanctions.

The committee also said Sunday that North Korea will “never pardon anyone who dares challenge its dignity, social system and its line of simultaneously developing” its economy and nuclear arsenal.

Seoul and Washington have warned that the North’s dual-track policy is a dead end for the communist country.

The North has called its nuclear programs a “treasured sword” against what it called Washington’s policy of hostility.

Earlier this month, the North called Park an “eccentric old spinster” and a “hen” over her comments on North Korea’s economic difficulties and its homeless children.

It is not unusual for the North to denounce leaders of South Korea and its key ally the U.S.

Last year, Pyongyang made a sexist swipe at Park by criticizing her “venomous swish of skirt,” which it said made South Korean officials engage in warmongering.

In 2009, North Korea’s foreign ministry described then U.S. Secretary of State Hillary Clinton as “a primary school girl” and “a pensioner going shopping” in response to her criticism of Pyongyang’s nuclear weapons program. (Yonhap)