But some in the exclusive nuclear club felt the commitment was not sufficiently binding on New Delhi.

Six NSG nations had been demanding a clause stipulating an automatic cessation of the waiver if India tested another bomb.

After India's statement, the holdout group splintered as Norway, the Netherlands and Switzerland indicated they could accept more limited language, diplomats said.

But Ireland, Austria and New Zealand rejected amended language presented to them individually by US officials on Friday evening as inadequate, several diplomats told Reuters.

They said the meeting broke down when China walked out in support of Ireland, Austria and New Zealand.

"The Americans have bullied them, including with high-level phone calls to their capitals, but they held firm because the US has showed no flexibility on testing," said one diplomat.

"The (revised text as it stands) gives no clear consequences for India if it tests, only a special meeting if that happens and that does not commit the NSG to take action," said another.

Decisions by the nuclear export cartel must be unanimous.

Washington says the nuclear cooperation deal with New Delhi would forge a strategic partnership with the world's largest democracy, help India meet exploding energy demand in an environmentally friendly way and open a nuclear market worth billions of dollars for Western firms.

NSG critics fear India could use access to nuclear material markets indirectly to boost its bomb programme and drive nuclear rival and fellow NPT outsider Pakistan into another arms race.