Party colleagues of former Indian prime minister Atal Behari Vajpayee say they are stunned by his decision to retire from active politics.
Mr Vajpayee will no longer be a part of the BJP's campaign trail
Members of his Bharatiya Janata Party (BJP) say they hope to persuade him to stay on and fight the next election.
On Thursday, Mr Vajpayee told a BJP rally in Mumbai he would not stand and was bowing out of "power politics".
Mr Vajpayee, 81, helped found the BJP and led a coalition government for six years until electoral defeat in 2004.
The BBC's Zubair Ahmed in Mumbai (Bombay) says there was a deafening silence at Thursday's rally when Mr Vajpayee made his announcement.
The meeting ended abruptly, without the former prime minister delivering the keynote speech at the end of five days of celebrations to mark the party's silver jubilee.
Some BJP members say they hope he will change his mind.
"We will try to convince him to contest the next election," a BJP member and former Indian minister, Shahnawaz Hussain, said. "[His decision] came as a surprise to us."
Others say they are encouraged by the fact that Mr Vajpayee has said he will continue to advise the party.
"The party will not get affected by his exit because he will continue to guide us," a BJP member from Gujarat, Bhagwan Singh Chauhan, said.
"We need his guidance."
Tributes to Mr Vajpayee have also come in from Pakistan which has praised him for his role in the peace process between the two countries.
Peace with Pakistan may prove Vajpayee's greatest legacy
"He was a simple but mature politician who played a leading role in the peace process between the two countries," Pakistan's Information Minister, Sheikh Rashid Ahmed, told AFP news agency.
"It is sad news. I must say that the peace process has slowed down after Vajpayee."
Mr Vajpayee initiated a peace process with Pakistan in 2004, two years after the two countries came close to war.
Over the past two years, India and Pakistan have taken a number of steps towards peace and many analysts credit Mr Vajpayee for the positive change in relations between the two nuclear-armed neighbours.
Mr Vajpayee's announcement came two days before LK Advani is due to step down as BJP president.
Both men helped found the right-wing BJP 25 years ago and were responsible for the party's meteoric rise to power.
Analysts say the party will now be run by a younger generation of leaders and faces an uncertain future.
Often described as the moderate face of the Hindu-nationalist BJP, Mr Vajpayee had developed a wider appeal than his more hardline colleagues.