NEW DELHI: Defence Minister Nirmala Sitharaman and her US counterpart James Mattis today held comprehensive talks on deepening bilateral military ties, including supply of advanced defence technologies to India.

Asserting that the defence partnership is one of the "key strategic pillars" of cooperation between India and the US, the two leaders agreed to explore additional and specialised exercises between the militaries of the two countries.

The armies of the two countries are currently participating in the joint military drill Yudh Abyas 2017 and their navies recently concluded in Bay of Bengal, the 2017 edition of Malabar, a trilateral exercise between India, the US and Japan.

While no specific defence trade deal was announced during Mattis' India visit, sources said there were talks on two specific proposals of F-16 and F-18A under Modi's Make in India campaign, along with efforts to identify new projects under the ambitious Defence Technology and Trade Initiatives (DTTI).

The Trump administration wants to sell F-18 and F-16 fighter planes to India, built by American companies Boeing and Lockheed Martin respectively. Both companies have offered to assemble these planes in India.

India is also keen on buying drones and Unmanned Ariel Vehicles (UAVs) from the US.

"We also discussed ways to further deepen the robust defence trade, technology collaboration between our defence industries. We look forward in assuring some of our most advanced defence technologies through the Defence Technology and Trade Initiatives (DTTI)," Mattis said during a joint- press briefing after his talks with Sitharaman.

The two sides deliberated on how to move forward on India's Major Defence Partner designation.

Sitharaman said the move will "provide further energy and momentum to our collaboration on defence technology and manufacturing".

Mattis noted that designation to India as the Major Defence Partner recognises India as a pillar of regional stability and security.

"The US is now a leading supplier of state-of-the-art defence equipment to India. I appreciated Secretary Mattis' willingness to share further cutting-edge platforms which would enhance India's defence preparedness to meet current and emerging threats," Sitharaman said.

In the wake of rising assertiveness of China in the Indo-Pacific region, especially in the hydro-carbon rich South China Sea, Mattis emphasised on enhancing maritime cooperation between the two nations.

"We appreciate India's stabilising leadership in the Indian Ocean and seek to work together to build a resilient and regional architecture," the defence secretary said.

On her part, Sitharaman said she also discussed with Mattis the issues relating to maritime security in the Indian Ocean and the broader Asia-Pacific Region as well as regional connectivity issues.

"India supports the freedom of navigation, over-flight and unimpeded lawful commerce. We also believe that disputes should be resolved through peaceful means and in accordance with the universally recognised principles of international law," she said, without making any reference of China.