It is rare for US congressmen to receive letters concerning human rights issues in Qatar. But when the tiny, energy rich Gulf state recently stripped some 6,000 men, women and children of their citizenship, leaving many in stateless limbo, US officials say the letters started rolling in.

Members of the al-Ghfran clan, a sub-set of one of Qatar's largest tribes, say their ordeal began late last year. Officially their Qatari citizenship was revoked on grounds that they hold dual nationality with neighbouring Saudi Arabia. But diplomats point out that many other dual nationals in Qatar have not been affected.