South Korean officials on Wednesday arrested a leftist activist for allegedly praising archrival North Korea, just days after an American was deported on similar charges and adding to criticism that the government seeks to limit free speech and suppress dissidents.

The Seoul prosecutors' office arrested Hwang Sun soon after the Seoul Central District Court issued an arrest warrant, according to court spokesman Kim Dae-hyun. Hwang is the former spokeswoman for a now-disbanded leftist party and has long been hounded by claims she supports Pyongyang.

In an Internet talk show she hosted between 2011 and 2013, Hwang dressed in black and mourned the death of former North Korean leader Kim Jong Il in late 2011. She also introduced an editorial of the North's main Rodong Sinmun newspaper.

Hwang angered conservatives in 2005 when she gave birth by cesarean section during a visit to Pyongyang.

Over the weekend, the Justice Ministry deported American travel writer Shin Eun-mi because of similar accusations that she had praised the North. Shin appeared with Hwang in lectures about North Korea last year.

"It's possible that the (National Security Law) could be abused by those in power to suppress their political rivals or create social fear. The recent events suggest that these worries are warranted," the liberal Hankyoreh newspaper said in an online editorial Wednesday.

In December, a high school student threw a homemade explosive device toward a podium where Hwang and Shin were speaking, injuring two people. Hwang and Shin were unhurt. The student was sent to a juvenile detention center and is awaiting trial.

The Korean Peninsula remains technically in a state of war, split along the world's most heavily fortified border, because the 1950-53 Korean War ended with an armistice, not a peace treaty. In South Korea, praising North Korea can be punished by up to seven years in prison under the National Security Law.

Supporters argue that the law is needed because of continuing threats from North Korea. But critics want it scrapped. Past authoritarian leaders in South Korea frequently used the law to suppress political rivals.