TOKYO: At least six people were reported injured on Tuesday, a day after a powerful quake rattled northern Japan, but there appeared to be no major damage from the tremor that also triggered tsunami waves up to 80 centimetres (31 inches).

However, the Japan Meteorological Agency (JMA) also warned of an increased risk of a megaquake — a tremor with a magnitude of 8.0 or stronger — hours after Monday’s 7.7 magnitude quake in Pacific waters off northern Iwate prefecture.

The jolt was so intense that it shook large buildings in the capital Tokyo, hundreds of kilometres from the epicentre.

Six people were reported injured by 8am (2300 GMT Monday), two seriously, the Fire and Disaster Management Agency (FDMA) said in a statement.

There were no reported fire outbreaks or damage to important facilities, it said.

Japan issued a warning for tsunami waves of up to three metres (10 feet) but it was lifted hours after an 80-centimetre (31-inch) wave hit a port in Kuji in Iwate, one among a series of small waves that hit elsewhere in northern Japan.

The JMA said that “the likelihood of a new, huge earthquake occurring is relatively higher than during normal times”.

Municipalities in the affected region issued non-compulsory evacuation directives to more than 182,000 residents, the FDMA said.

Japan is one of the world’s most seismically active countries, sitting on top of four major tectonic plates along the western edge of the Pacific “Ring of Fire”.

The archipelago, home to around 125 million people, typically experiences around 1,500 jolts every year and accounts for about 18 percent of the world´s earthquakes.

The vast majority are mild, although the damage they cause varies according to their location and the depth below the Earth´s surface at which they strike.

Japan is haunted by the memory of a massive 9.0 magnitude undersea quake in 2011, which triggered a tsunami that killed or left missing around 18,500 people and caused a devastating meltdown at the Fukushima nuclear plant.

A US delegation led by Vice President JD Vance is en route to Pakistan and expected to land in Islamabad within hours for the second round of talks with Iran, President Donald Trump said on Monday.

Trump confirmed the development in an interview with the New York Post, saying he would be willing to meet Iranian leaders himself if progress is made in the talks.

Apart from Vance, the US delegation includes Trump’s son-in-law, Jared Kushner, and Special Envoy to the Middle East Steve Witkoff, as per a report by Axios.

If reports about the other delegation members are accurate, it would mean the US delegation is the same as in the first round of Iran talks held in Islamabad on April 11.

However, a source familiar with the plan told AFP on Monday that a US delegation will head to Pakistan “soon” for a new round of peace negotiations with Iran.

Meanwhile, mediator Pakistan — which brokered a two-week ceasefire between the two sides on April 8 — was making efforts to end the US naval blockade of Iranian ports and to ensure Iran’s participation in the peace talks.

With the ceasefire set to expire, a senior Iranian official told Reuters that Tehran was “positively reviewing” its participation following Pakistan’s efforts, but no final decision had been made.

The comments conveyed a clear change of tone from earlier statements ruling out attendance and pledging to retaliate for US aggression.

Separately, Deputy Prime Minister and Foreign Minister Ishaq Dar held a phone call with Iranian Foreign Minister Abbas Araghchi, emphasising the importance of continued dialogue and engagement to resolve all pending issues.

DPM Dar stressed that persistent dialogue was essential to ensure regional peace and stability, read a statement issued by the Foreign Office.

Since the announcement of the ceasefire, Tehran and Washington have disagreed on a number of issues, including Iran’s blockade of the Strait of Hormuz and the US naval blockade of Iranian ports.

Tehran effectively blocked the waterway and launched attacks against Israel and US bases across the Middle East in response to the joint US-Israel attacks on February 28.

Iranian Foreign Minister Abbas Araghchi, on April 17, announced the reopening of the strait for commercial vessels following the ceasefire in Lebanon.

However, Iranian authorities blocked the waterway again the following day, citing the US blockade of Iranian ports.

On April 18, the Islamic Revolutionary Guard Corps (IRGC) said that the US blockade represented “acts of piracy and maritime theft”.

“Until the US restores full freedom of navigation for vessels travelling from Iran to their destinations and back, the status of the Strait of Hormuz will remain tightly controlled and in its previous condition,” it said.

US Marines board Iranian vessel

The ceasefire had appeared in jeopardy after the US said it had seized an Iranian cargo ship that tried to run its blockade, and Tehran vowed to retaliate.

The US military said it had fired on an Iranian-flagged cargo ship headed towards Iran’s Bandar Abbas port on Sunday after a six-hour standoff, disabling its engines.

US Central Command released a video showing Marines descending ropes from helicopters onto the vessel.

Iran’s military said the ship had been travelling from China and accused the US of “armed piracy”, according to state media.

They said they were ready to confront US forces over the “blatant aggression”, but were constrained by the presence of crew members’ families on board.

Trump on Sunday warned that the US would destroy every bridge and power plant in Iran if it rejected his terms, continuing a recent pattern of such threats.

Iran has said that if the US were to attack its civilian infrastructure, it would strike power stations and desalination plants in its Gulf Arab neighbours.

Iran’s President Masoud Pezeshkian says strengthening unity among Islamic countries is the most important way to counter conspiracies and prevent foreign powers from taking advantage.

Speaking during a supervisory visit to the Ministry of Justice on Monday, Pezeshkian received a comprehensive report on the ministry’s actions and missions under the special circumstances resulting from the recent US-Israeli aggression.

Pezeshkian noted that through “empathy, honesty, and collective participation, we can get past this stage and continue the country’s path toward dignity and progress.”

He highlighted the need for a rational approach toward regional and international developments, adding, “War benefits no one. While standing firm against threats, we must use every rational and diplomatic path to reduce tensions.”

He further noted that distrust toward the enemy and vigilance in interactions remain an undeniable necessity.

Following the US and Israel’s recent aerial strikes on Iran launched on February 28, Iran retaliated with barrages of missile and drone attacks on Israeli-occupied territories and US bases and interests in the region.

The president noted that passing through the battlefield does not mean the end of the road. Rather, it marks the beginning of a more important phase: the ‘Greater Jihad.'”

He described this as a struggle in which all people must play a role through patience, tolerance, cooperation, and active participation in rebuilding the country and solving its problems.

“This phase requires greater mental and social readiness than the war era,” he added.

Referring to the decisive role of the guidance of the Leader of the Islamic Revolution Ayatollah Seyyed Mojtaba Khamenei and martyr Leader of the Islamic Revolution Ayatollah Seyyed Ali Khamenei, Pezeshkian stated, “The support and directives of the great and martyred Leader of the Revolution have been a solid pillar for the government since the very beginning of its work.

“It was the coordination formed in the light of these guidelines that today makes effective decision-making and overcoming challenges possible,” he highlighted.