Qatar has accused Saudi Arabia of barring its nationals from performing this year's Hajj, a charge Saudi officials deny.
Around 1,200 Qatari citizens are allowed to attend the pilgrimage under a quota system, but Qatari officials say it has become impossible to register for the annual religious event.
Saudi Arabia, alongside the United Arab Emirates, Bahrain and Egypt, severed relations with Qatar in June 2017, and has placed the Gulf state under a land, sea, and air blockade.
Qatari nationals are also banned from entering the states, but Riyadh claims to have made an exception for the Hajj.
Al Jazeera's Laura Burdon-Manley reports from Doha.