India's dream of landing its first unmanned mission on the moon suffered a blow today as the journey of the lander of the Chandrayaan-2 failed to go as per the script and lost communication with Indian Space Research Organization's ground stations during the descent on the moon's surface.

The contact was lost with the lander when it was 2.1km away from the moon's south pole, an unexplored area of moon, our New Delhi correspondent reports.

The landing would have made India the fourth country -- after the United States, Russia and China -- to successfully land on the moon.

Indian Prime Minister Narendra Modi, who watched the operation live from the Indian Space Research Organization's mission control centre in Bengaluru, later asked the ISRO scientists not to "lose hope".

"We came very close but we need to cover more ground.... Learning from today will make us stronger and better," Modi told the ISRO scientists adding, "The best is yet to come in our space programme. India is with you."

Addressing the scientists, he said he could sense their disappointment and asked them not to lose hope. "I see disappointment on your faces. No need to get dejected. We have learnt a lot."

"These are moments to be courageous and courageous we will be! We remain hopeful and will continue working hard on our space programme", he added.

"There are ups and downs in life. This is not a small achievement. The nation is proud of you," said Modi to the ISRO scientists.

The failure happened 13 minutes after the lander, named Vikram after Vikram A Sarabhai, the father of India's space programme, began its descent.

Modi, who had joined the scientists 15 minutes before the lander's descent began, was briefed by a ISRO Chairman K Sivan on contact being lost with the lander.

Several minutes after the landing time was over Sivan announced that communication had been lost with the lander.

"Vikram lander descent was as planned and normal performance was observed up to an altitude of 2.1 km. Subsequently, the communications from the lander to ground stations was lost," Sivan said.

"The data is being analysed," he added.

A senior ISRO official closely associated with the mission said later, "There is no communication with the lander. It's as good as lost. There is no hope. Very difficult to re-establish contact".

The 1,471-kg lander of Chandrayaan-2, which was launched from India's space port in Sriharikota on July 22, was the first Indian mission to explore the lunar terrain with home-grown technology and was designed to execute a soft landing on the lunar surface to function for one lunar day, which is equivalent to about 14 earth days.

The lander carried three scientific payloads to conduct surface and subsurface science experiments while the rover inside the lander carried two payloads to enhance our understanding of the lunar surface, according to ISRO.

As the powered descent of the lander began at around 1:38 am, scientists at ISRO Telemetry Tracking and Command Network (ISTRAC) were glued to their terminals, anticipating the soft landing.

They clapped and cheered as the moon lander completed the rough braking phase before the fine braking phase started. It was then that the scientists started becoming tense and went into a huddle. Sivan was seen engaged in intense discussions with some scientists.

Besides the Indian Prime Minister, morale-boosting messages poured in from various quarters for ISRO as several leaders asked the space agency not to get disheartened.

Expressing solidarity with the scientific community, India's Finance Minister Nirmala Sitharaman tweeted, "We are with you ISRO. You have brought the nation, its young minds and all, together in sensing your achievements in Space. You will succeed."

Minister for Science and Technology Harsh Vardhan urged the scientists not to give up and that success was failure turned inside out. "The silver tint of the clouds of doubt You never can tell how close you are It may be near when it seems so far.

He was optimistic that the ISRO scientists would accomplish the mission in the future.

In a tweet, Home Minister Amit Shah said ISRO's achievement with getting Chandrayaan-2 so far has made every Indian proud and added that the country stood with the committed scientists of ISRO.

While congratulating ISRO, Congress leader Rahul Gandhi said their work was not in vain. "It (Chandrayaan-2) has laid the foundation for many more path breaking and ambitious Indian space missions," he said.

Delhi Chief Minister Arvind Kejriwal said there was no need for ISRO to lose heart. "Our scientists have done a great job," he tweeted.