A multi-nation naval exercise, including warships from the US, Russia and China, kicked off in the Arabian Sea off Karachi on Friday as part of 'Aman-17' being hosted by Pakistan.

The four-day exercise, with 37 countries taking part, has the theme 'Together for peace'. It is the fifth such exercise that Pakistan has been holding since 2007.

In a message, Prime Minister Nawaz Sharif said that Pakistan is fully committed to ensuring freedom of navigation and lawful maritime order.

The other navies joining in include Australia, Indonesia, Japan, Malaysia, Turkey and Britain.

Russia's Severomorsk anti-war ship, Altay Tug Boat and Dubna tanker are part of the exercise, while China's 24th escort naval fleet is taking part in the joint drill with its missile destroyer Harbin, guided-missile frigate Handan and supply ship Dongpinghu. Around 700 troops are also participating. It's the fifth time that China has joined AMAN exercise since its launch.

Commander of the Pakistani naval fleet Vice Admiral Arifullah Hussaini inaugurated the exercise at the Karachi dockyard.

Hussaini, speaking at the ceremony, said the exercise would help work against human trafficking, narcotics smuggling, and terrorism in the region, Radio Pakistan reported.

He considered the exercise a good platform for all navies to exchange ideas, enhance mutual understanding and cooperation.

"Aman exercise provides a chance for us to exchange ideas and reinforce our communication with other navies," said Chinese Captain Yu Tao of missile destroyer Harbin. 

Due to an increasingly challenging maritime environment, the Chinese navy should enhance its cooperation with other countries and learn others' expertise to better fulfil its escort missions, he said.

Initiated and organised by Pakistan, the "Aman" series exercise has been held every other year since 2007, aiming to boost inter-operability and to demonstrate the allied nation's capabilities to fight terrorism and other maritime threats.

Sharif pointed out that maritime security challenges in the Indian Ocean were both multidimensional and multifaceted. Threats such as maritime terrorism, drug trafficking and piracy have acquired international dimensions, he said.

Sharif emphasised that cooperation between international navies was imperative to countering emerging threats.