MBS aide boasts plan to dig trench around Qatar
Saudi Arabia, the UAE, Bahrain and Egypt launched a blockade on Qatar last June, cutting diplomatic ties with Doha and halting air, sea and land links to the Gulf state.
The Saudi-led bloc accuses Qatar of supporting terrorism and being too closely allied to regional rival Iran, claims Doha strongly denies.
Reports about the canal first emerged in April, with unnamed sources describing to local media Saudi plans to build a nuclear waste dump and military base along its 60-kilometre border with Qatar.
Months later, Riyadh announced that 25 June would be the last day for tenders to bid for the so-called "Salwa Canal" project, which would span the border.
The move has been widely criticised and viewed as a way of trying to further isolate Qatar for not towing the Saudi-UAE line on regional issues.
"As a citizen, I am impatiently waiting for the details of the implementation of the East Salwa island project, this great historic project that will change the region's geography," Saud al-Qahtani, a senior adviser to Saudi Crown Prince Mohammed bin Salman, wrote on Twitter.
Qahtani has repeatedly mentioned the canal project on Twitter over the past few months, retweeting memes boasting about turning Qatar into an island.
Friday's tweet, however, is the clearest reference yet that the initiative is a serious plan rather than an intimidation tactic.
Just months after the Saudi-led blockade of Qatar last year, Qahtani launched on Twitter a McCarthyist appeal to Saudis to compile a blacklist containing the names and identities of anyone showing sympathy with Qatar under the Arabic hashtag #TheBlacklist.
Saudi Arabia and the UAE launched a sustained, but unsuccessful, media campaign against Qatar since the June blockade began.
Any attempt to redesign the geography of the Arabian Peninsula to isolate Qatar would be considered illegal under international law.