The outpouring of public support in South Korea for U.S. Ambassador Mark Lippert following the bloody attack on him last week is a testament to the strength of relations between the two countries, the State Department said Monday.

South Koreans have been expressing support on and offline for the top American envoy after a knife-wielding man slashed him on the face and wrist, prompting concern the incident could hurt the alliance with the U.S., a key element of the country's defense against North Korea.

South Korean President Park Geun-hye paid a visit to Lippert at the hospital right after returning from a trip to the Middle East on Monday morning. Prime Minister Lee Wan-koo, Foreign Minister Yun Byung-se and other top government officials have also visited him.

"South Korea remains one of our most important partners. That will continue and obviously, their response, their outpouring of support, the fact that President Park went and visited Ambassador Lippert ... speaks to the strength and vitality of our relationship," State Department spokeswoman Jen Psaki said at a regular briefing.

Psaki said Lippert is in stable condition and is expected to leave the hospital Tuesday afternoon.

"The ambassador, as you may have seen on Twitter, is active and in good spirits. He's resting comfortably in the hospital," she said. "He also again reiterates his deep gratitude for all the messages of concern and support from friends in the Republic of Korea and the United States, including the visit by President Park, to his hospital room."

The attack left Lippert with wounds that required 80 stitches.

The 55-year-old attacker was immediately arrested, and as he was hauled away, he shouted opposition to joint military exercises under way between South Korea and the U.S., something in line with North Korea's rhetoric.

Psaki declined comment on whether it's possible for the U.S. to put North Korea back on the list of state sponsors of terrorism if the assailant is found to have a link to Pyongyang.

"Well, that's several steps ahead of where things are. We'll let the investigation play itself through," she said. "I'm not going to speculate on the motivation. Obviously, there have been a range of reports, but the government of South Korea has the lead on this investigation. Beyond that, I'm just not going to speculate." (Yonhap)