Susan Schwab, the US trade representative, said China and India were "advocating selectively reopening the package".
"There is a real threat to a delicate balance we've achieved on Friday night and I'm concerned it will jeopardise the outcome of this round," she said after Monday's meeting.
But Kamal Nath, India's commerce minister, rejected suggestions he was deliberately holding up the talks.
"Who's holding up this round I think are the large developed countries ... who are looking for commercial interests and enhancing prosperity rather than looking for content which reduces poverty," he said.
Nath described the discussions over "contentious issues of livelihood security" as "intensive" and Keith Rockwell, a spokesman for the WTO, described the atmosphere at the talks as "very tense".
"The situation is very tense, things are finely balanced and the outcome is by no means certain," Rockwell told reporters earlier.
Raj Petal, a trade analyst, told Al Jazeera that "the European Union and the United States have kind of fixed the rules of the game".
"The EU and the US are allowed to support their agriculture to the tune of billions of dollars a year ... but developing countries are not allowed to have similar programmes in place. It's still a very asymmetrical game.
Talks to rescue the trade deal will continue on Tuesday with negotiators trying to avert a collapse, ministers said.
Mariann Fischer Boel, the EU agriculture commissioner, admitted the eighth day of talks had been "an emotional roller-coaster" but promised "we will be back tomorrow with strong commitments to continue the negotiations".
But Petal told Al Jazeera that "there's not much reason to think that we can get the kind of agreement that would drive forward a trade agenda".
"There's actually quite a lot of discord in the international community at the moment and that makes the prospect of an agreement fairly distant."
Top trade officials from around 30 WTO members have been in Geneva since last Monday struggling to bridge differences on subsidies and import tariffs to forge a new deal under the WTO's Doha Round of negotiations, which has repeatedly foundered since it was launched seven years ago.