According to reports, no visitors are allowed to meet the Congress President.
"Sonia Gandhi is back and in good health. I cannot say anything more on this matter," said Rashid Alvi, newly appointed Congress spokesperson.
"As doctors have advised her complete rest, she is not meeting party colleagues," said a senior congress member who refused to be named.
"I only know what all others know through media reports. There has been no communication from the NAC Secretariat on her illness," said Aruna Roy, member, NAC headed by Sonia Gandhi.
"I hear she is improving and will be resuming duties after a month. Visitors are not permitted now. Otherwise, party leaders will flock to 10 Janpath," said another party leader.
The party leader, who wished to remain anonymous said that he and his party members were aware of rumours doing the rounds that Sonia's condition was serious.
"I know that our rivals, both from the Left and the Right, are spreading these rumours," he added.
Neither the Congress nor the Gandhi family officially announced what ailment Sonia was suffering from.
"The family is maintaining strict privacy about Sonia's illness," said the official.
"Most Congress leaders did not even know about her leaving for the US till it was announced by the party spokesperson," he said.
Sonia has not attended any event after her return from US to India.