Seoul, May 18 (IANS): South Korea and the US have a "Plan B" ready in case North Korea carries out a provocation during American President Joe Biden's visit to Seoul this week, an official said here on Wednesday.

"At the moment, we assess that the possibility is relatively low of North Korea carrying out a nuclear test by the weekend, but preparations for an intercontinental ballistic missile launch are believed to be imminent," Kim Tae-hyo, first deputy chief of the presidential National Security Office, told reporters.

In case the North undertakes a provocative act during Biden's visit, the South and the US have prepared a "Plan B" to ensure the combined defence posture between the two countries, Yonhap News Agnecy quoted Kim as saying.

The official however, did not provide any further details.

Biden is set to arrive in Seoul on Friday for his first summit with President Yoon Suk-yeol.

Yoon and Biden will likely agree during Saturday's summit to add another "technological" pillar to the bilateral alliance, Kim said.

The official also said the US recently offered to send Covid-19 aid to North Korea to help the country contain a massive outbreak but received no response.