The war of words between Amazon and Flipkart escalated on Tuesday, with one of Flipkart’s exclusive television brands coming out strongly against Amazon India for selling their products, worsening already prickly relations between India’s largest online marketplaces.

VU, which has an exclusive partnership with Flipkart and currently accounts for roughly 40% of the online retailer’s overall television sales, has warned customers not to buy its television sets from any other online marketplace.

Amazon India, however, defended the sale of VU TVs on its platform, saying that products are directly sold by independent sellers on its platform.

As you are aware, Amazon.in is a marketplace and products are listed on Amazon.in by independent sellers,” an Amazon India spokeswoman said in an email.

VU’s latest public missive on Tuesday comes on the heels of last week’s controversy with OnePlus, which currently has an exclusive tie-up with Amazon in India.

Last week, OnePlus co-founder Carl Pei publicly expressed his dismay at OnePlus devices selling on Flipkart and shot an angry tweet at Flipkart co-founder and executive chairman Sachin Bansal.

“@_sachinbansal brother, what’s this? We’re exclusive with @amazonIN,” Pei had tweeted to Bansal. Bansal did not reply to Pei.

Shortly after, OnePlus warned customers not to buy its devices from any other online platform.

“We are exclusive with @amazonIN and advice users to buy OnePlus through official channels. We can’t guarantee the authenticity elsewhere,” OnePlus had tweeted last week.

On Tuesday, VU strongly came out and warned customers not to buy its television sets from any other online channels as they might not be genuine products.

VU TVs are sold exclusively on Flipkart. VU has benefited from Flipkart’s wide reach, extensive logistics capability along with its network of service engineers. VU has not authorized the sale of VU TVs on any other online platform. In the interest of our consumers, any VU products sold elsewhere online other than Flipkart, may not be of genuine quality,” said Devita Saraf, chief executive of VU Technologies, in an interview.

“Customers who purchase VU TVs on other online platforms will not be covered under the company’s warranty service and the customer service that you are automatically entitled to if you buy our TVs on Flipkart,” Saraf added.

The latest war of words related to the sale of exclusive brands on Flipkart and Amazon escalates already heightened tension between the two rivals, as competition to win over the next generation of Indian online shoppers, with billions of dollars at stake, has intensified .

In October, after triumphing over Amazon during the crucial Diwali season sale, Flipkart chief executive Binny Bansal took a swipe at Amazon, saying the American e-commerce giant had misjudged customers’ needs during the festive season sale by focusing on sale of groceries, which helped inflate Amazon India’s sales numbers, according to Bansal.