Prime Minister Narendra Modi made a surprise visit to India's northern frontier region with China on Friday in his first trip to the area since a deadly border clash last month.

The incident in the Galwan Valley saw 20 Indian troops killed and was the first time in 45 years that soldiers had died in combat on the Asian giants' long-disputed Himalayan border.

Modi toured a military base at Nimoo in Ladakh, about 100 kilometres (60 miles) as the crow flies from the site of the June 15 battle. 

He was due to go to a military hospital in nearby Leh to meet soldiers injured in the hand-to-hand skirmish, a security source told AFP.

The head of India's military and the army chief also joined the visit to the sensitive area, which has been used as a staging post to build up troop numbers in the region.

China also suffered casualties but has not given details.

Both sides have blamed each other for the incident and since sent thousands of extra troops to the region. 

They have held several rounds of military-level talks and said they want a negotiated settlement but have made little apparent progress.

India has also attempted to turn the screws on China economically, this week banning 59 Chinese mobile phone apps including the popular TikTok citing national security concerns.

With anti-China sentiment on the rise locally, Chinese imports including raw materials vital to India's pharmaceutical industry have reportedly been piling up at Indian ports due to more stringent border checks.