The United States is believed to have deployed an additional submarine armed with 150 Tomahawk cruise missiles to the Middle East as part of a growing military buildup, while Iran's Defence Ministry claims the country has significantly strengthened its missile capabilities since the 12-day conflict with Israel in the summer.

The submarine has joined an American naval squadron led by the aircraft carrier Abraham Lincoln, which is carrying four fighter squadrons and heading towards the Arabian Sea, Western media reported on January 24.

Destroyers equipped with long-range Tomahawk missiles are also part of the deployment, according to sources in Russian media monitoring the situation in the Persian Gulf and Arabian Sea.

Tehran has warned that any military strike against Iran would be considered the beginning of a full-scale war and would provoke the harshest possible response, according to the reports.

Brigadier General Reza Talaei-Nik, spokesman for Iran's Defence Ministry, said the Islamic Republic's missile power has increased compared to the 12-day war, Khabaronline reported on January 24.

He claimed the country's missile defence capability has been reinforced using lessons from that conflict, with locally production of missiles increasing since the summer to make up the loss of those delivered to Israel and Qatar earlier.

"In terms of quantity and quality, the missile power capabilities of the Islamic Republic of Iran have increased compared to the 12-day imposed war," Talaei-Nik said, according to Fars News Agency.

The military escalation comes as Iran has reportedly contained domestic unrest that erupted in late December but came to an deadly stop when militants from Iran and neighbouring allied countries were released on the streets. Iran's own mortality figures are as high as 3,110, while foreign estimates claim the death toll is significantly higher. 

Protests that initially focused on economic grievances evolved into political demands, with some demonstrators calling for the return of Reza Pahlavi, the Shah's son, who was overthrown more than 47 years ago.

​Talaei-Nik stated that Iran now possesses greater capacity for resistance and confrontation against any conflict or enemy aggression compared to the past. He said enemy vacillation in rhetoric and threats demonstrates Iran's power, though authorities refrain from unveiling specific missile capabilities to maintain the element of surprise.

US President Donald Trump has pledged to protect the protesters. Iranian authorities claim Washington and Israel are actively fomenting the internal unrest, though no evidence for these allegations was provided.

Concurrently, multiple unknown vessels, including Iranian and British-flagged ships, have been tracked in close proximity near Kooh Mobarak off Iran's southern coast, according to maritime tracking data reviewed on January 23.

Kooh Mobarak lies along Iran's coastline near the approaches to the Strait of Hormuz, through which approximately one-fifth of global oil consumption passes. The waterway connects the Persian Gulf with the Gulf of Oman and remains a critical chokepoint for international energy shipments.

Automatic Identification System data showed at least six vessels operating in the area, including the Iranian-flagged vessels Toofio, Mahdi Javed, Mahdi Boya and Abobakr 83, alongside British-flagged Armin 1 88 and the unspecified Armin 2 99. All vessels were recorded as Class B navigational status.