Rohit Jaggi and Tom McCawley, Jakarta – Indonesian President Abdurrahman Wahid's hold on power grew increasingly tenuous on Thursday after his vice-president broke her silence to stress that she did not support him.

Mr Wahid's predicament was highlighted by Fahmi Idris, parliamentary chairman of Golkar, the second-largest party, who said: "The clear solution to this nation's problems is that Gus Dur [Mr Wahid's nickname] had better quit."

Mr Wahid is under pressure to resign after parliament last month issued him with a formal warning over his alleged involvement in two financial scandals. If Mr Wahid fails to give a satisfactory response to parliament, a special session of the country's highest legislative body could be called to oust him and install his deputy in his place.

"In August the special session will happen," Mr Fahmi said on Thursday.

Vice-President Megawati Sukarnoputri emphasised to a Muslim organisation this week that she had been co-operating with Mr Wahid only because of her position as vice-president, and that she did not support him. Her statement was echoed by Akbar Tandjung, chairman of Golkar.

Mrs Megawati "is being more forceful", Arifin Panigoro, vice-chairman of her party, the Indonesian Democratic Party-Struggle (PDI-P), said on Thursday. "Before she only disclosed [her lack of support for Mr Wahid] to her closest allies. But now she is more open. She is ready to become president."

The comments by Mrs Megawati and Mr Tandjung followed a claim in Cairo by Mr Wahid, who is on a 15-day trip to Africa and the Middle East, that they supported him. Mr Tandjung warned on Thursday that "Mr Wahid's position may be in jeopardy if he stays overseas".

The president has faced sharp criticism for refusing to return to Indonesia despite the eruption of an ethnic conflict in Kalimantan that has claimed more than 400 lives. Mr Arifin said his absence "is outrageous. It's unbelievable".

The PDI-P, the largest party in parliament, is working with the other main factions, including Golkar, on how to form a formal coalition to support Mrs Megawati's presidency.

Mr Arifin said the vice-presidency could be offered to the military, which "very strongly supports her", or be left vacant until the next election in 2004 to avoid diluting the presidency.

Protesters raised the temperature in Jakarta on Thursday with a demonstration calling for Mr Wahid to resign. Police scuffled with students outside the state palace.

Mr Wahid has denied any part in financial scandals and has refused to step down.