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 died in combat on the Asian giants' long-disputed Himalayan border. Mr Modi toured a military base at Nimoo in Ladakh, about 100 kilometres from the site of the June 15 battle. 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. Mr Modi chanted “Long live mother India!” while addressing troops at the Nimu military base, insisting that “after every crisis, India has emerged stronger”. He praised the valour of Indian soldiers and said: “Enemies of India have seen your fire and fury.” “Days of expansionism are over. Expansionism creates danger for world peace. This is an era of development. Expansionist force have either lost or forced to turn back,” he said in an oblique reference to China. Mr Modi’s speech, which lasted for 26 minutes, was punctuated by nationalist fervour and praise for Indian soldiers. He said the bravery shown by troops was “a message of India’s prowess” to the world. “The weak can never accomplish peace, the brave do. The world is praising the bravery shown by Indian soldiers in Galwan Valley,” he said. Mr Modi later visited a military hospital where he met injured soldiers. China also suffered casualties in the June 15 clash 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 TikTok, the popular video-sharing service, 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. China said on Friday that it would take “necessary measures to safeguard the legitimate rights and interests of Chinese enterprises in India” and warned New Delhi against making a “strategic miscalculation”. India should “work with China to safeguard the overall situation of bilateral relations”, Foreign Ministry spokesperson Zhao Lijian said a daily briefing. “India should not make a strategic miscalculation on China,” he said. Amid rising tensions, India's defence ministry on Thursday announced the purchase of 33 Russian fighter jets and upgrades to 59 others in deal worth $2.4 billion (Dh8.8bn). The purchase of 21 MiG-29 and 12 SU-30 MKI, as well as upgrades to 59 MiG-29s, was to "augment" the Indian Air Force's combat squadrons, the ministry said. New and additional missile systems to be manufactured in India were also commissioned for all three branches of the military. The beefing up of New Delhi's defence capabilities was taken due to "the need to strengthen the armed forces to protect our borders and Prime Minister Narendra Modi's call for 'Self-reliant India'", the ministry said. The announcement followed Mr Modi's phone call to Russian President Vladimir Putin to congratulate him after a nationwide vote on constitutional reforms that could allow him to extend his rule until 2026. Russia was New Delhi's Cold War ally and remains India's biggest armaments supplier. In 2018, the two countries signed an accord for Moscow to supply its S-400 missile system in a deal worth $5.4bn despite the threat of US sanctions. India in October received the first of 36 Rafale fighter jets ordered from France in 2016 as it seeks to renew its ageing fleet.