Kamala Harris has accused Israeli Prime Minister Benjamin Netanyahu of pulling the strings over US involvement.

North Korea launched multiple ballistic missiles toward the sea on Sunday, its neighbours said, the North’s latest weapons testing activity this year.

South Korea’s Joint Chiefs of Staff said the launches happened on Sunday morning from the North’s eastern Sinpo area.

It said South Korea has bolstered its surveillance posture and is closely exchanging information with the US and Japan.

South Korea's presidential office said its National Security Council plans to hold an emergency meeting to discuss the launches.

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Japan’s Defense Ministry also detected the launches, saying the weapons were believed to have landed in the waters off North Korea's east coast.

It said Tokyo strongly protested to Pyongyang, saying Sunday's launches threaten regional and international peace and violated UN Security Council resolutions that bans any ballistic activities by North Korea.

Last week, North Korea said leader Kim Jong Un supervised missile tests from the country’s destroyer.

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After the test, Kim said his government remained focused on the “limitless expansion” of its nuclear forces and issued unspecified new tasks to sharpen the country’s nuclear attack and rapid-response capabilities.

International Atomic Energy Agency Director General Rafael Grossi said last week that his agency has confirmed “a rapid increase” in activities at nuclear facilities in North Korea.

READ MORE: Pope rejects claims of feud with Trump over Iran war

US President Donald Trump has reacted to the closure of the Strait of Hormuz by saying "Iran can't blackmail us".

He says that American talks with Iran are going well and that he expects to have more information over the weekend, the Associated Press reports.

Trump declined to take reporters' questions about Iran but said, "We have very good conversations going on."

LIVE UPDATES: Iran fires on ships in Strait of Hormuz

He says Iran "got a little cute," later adding, "They wanted to close up the strait again," referring to the Strait of Hormuz.

"They can't blackmail us," Trump said.

The US president was speaking shortly after Iran's Islamic Revolutionary Guard Corps (IRGC) has announced it will blockade the Strait of Hormuz, the organisation's naval forces said in a statement on Telegram overnight.

"Approaching the Strait of Hormuz will be considered cooperation with the enemy, and any offending vessel will be targeted," the IRGC statement read.

After declaring the waterway open on Friday, Iran reimposed restrictions on the passage of ships on Saturday, citing "repeated breaches of trust" by the US in the two sides' ceasefire.

READ MORE: US Navy denies food shortages after grim photos emerge from blockade ships

The British military says two gunboats from Iran's Revolutionary Guard opened fire on a tanker transiting the Strait of Hormuz after Iran said it had reimposed restrictions on the vital waterway.

Hours later a container ship was hit by "unknown projectile which caused damage to some of the containers" about 46 kilometres off the coast of Oman, the UKMTO said.

– Reported with CNN, Associated Press

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