South Korea alert over North's possible rocket launch

South Korea is on alert over reports of a possible rocket launch by North Korea, media reports said Tuesday.

According to daily The Chosun, Seoul Joint Chiefs of Staff (JCS) is "closely monitoring any preparations by Pyongyang" after the North reportedly reactivated a missile launch site.

The South Korean Foreign Ministry confirmed that Seoul and Washington have been thoroughly following the North's movements at Dongchang-ri long-range missile launch site.

Early this month, reports had emerged that North Korea was "restoring an ancillary building" at Dongchang-ri, which was partially disassembled last year.

In a news conference Tuesday, a South Korean Foreign Ministry spokesman urged the North to make a "wise" judgment regarding reports of possible preparations for a missile or satellite launch, South's Yonhap news agency said.

"[South Korea] hopes that the North will make a choice, which will be helpful for all, through a wise judgment," spokesman Kim In-chul said.

The latest Trump-Kim summit ended without a deal as the two sides failed to bridge their differences over the scope of Pyongyang's denuclearization and Washington's sanctions relief.