It is the largest arms purchase in the country's history.

Estonia, which neighbours Russia, has increased defence spending since Moscow's invasion of Ukraine, as has its Baltic neighbours, Latvia and Lithuania.

The HIMARS systems delivered to Ukraine are widely seen as one of the most effective tools in its arsenal, as the pro-Western country fights back against Russian troops.

Magnus-Valdemar Saar, director general of the Estonian Centre for Defence Investments (ECDI), signed a contract on Friday with the United States' Defense Security Cooperation Agency to boost the country's indirect fire capability, the ECDI said in a statement.

Estonia will also "procure ammunition, communications solutions, as well as training, logistics, and life-cycle solutions", said armament category manager Ramil Lipp.

The ECDI did not provide details on how many rockets were ordered but said the purchase included those which can strike targets at a distance of 300 kilometres (186 miles), and rockets of shorter range.

The first deliveries will arrive in 2024.

Lithuania last month said it would buy eight HIMARS rocket systems from the United States for $495 million.