UN Secretary-General Antonio Guterres earlier this week had been adamant that Kuwait was best placed to lead efforts to defuse the crisis.
Tensions escalated, however, after Bahrain, Egypt, Saudi Arabia and the United Arab Emirates presented a list of demands to Qatar overnight.
These included the closure of Al-Jazeera, a downgrading of diplomatic ties with Iran and the shutdown of a Turkish military base in the emirate, according to the list that was leaked.
The list of demands has not been officially confirmed.
More From This Section
"We continue to follow the situation with deep concern. We are aware of reports of a list of demands on Qatar. We are not able to comment in detail on, or confirm such a list," added Kaneko.
Anwar Gargash, the UAE's state minister for foreign affairs, warned that Qatar should take the demands seriously or face "divorce" from its Gulf neighbors.
Qatar is a member of the Gulf Cooperation Council with Bahrain, Kuwait, Oman, Saudi Arabia and the UAE.
Other allies, including Bahrain and Egypt, followed.
Saudi Arabia regularly accuses Iran, its regional rival, of interference throughout the Middle East.