Israeli warplanes carried out late on Thursday their most intense strikes on southern Lebanon in nearly a year of war, heightening the conflict between Israel and Lebanese armed group Hezbollah amid calls for restraint.

The White House said a diplomatic solution was achievable and urgent, and Britain called for an immediate ceasefire between Israel and Hezbollah. The U.S. is "afraid and concerned about potential escalation," White House spokesperson Karine Jean-Pierre told a briefing, Reuters reported.

The intense barrage followed attacks earlier in the week attributed by Lebanon and Hezbollah to Israel that blew up Hezbollah radios and pagers, killing 37 people and wounding about 3,000 in Lebanon.

In Thursday's late operation, Israel's military said its jets over two hours struck hundreds of multiple-rocket-launcher barrels in southern Lebanon that were set to be fired immediately toward Israel.

The bombardment included more than 52 strikes across southern Lebanon after 9 p.m.(1800 GMT), Lebanon's state news agency NNA said. Three Lebanese security sources said these were the heaviest aerial strikes since the conflict began in October.

There were no immediate reports of casualties.

Israel's military vowed to continue to attack Hezbollah and said its strikes throughout Thursday hit about 100 rocket launchers plus other targets in southern Lebanon.

In a TV address on Thursday, Hezbollah leader Hassan Nasrallah said the device explosions on Tuesday and Wednesday "crossed all red lines".

"The enemy went beyond all controls, laws and morals," he said, adding the attacks "could be considered war crimes or a declaration of war."

Israel has not directly commented on the pager and radio detonations, which security sources say were probably carried out by its Mossad spy agency, which has a long history of carrying out sophisticated attacks on foreign soil.

The Lebanese mission to the U.N. said in a letter to the Security Council on Thursday that Israel was responsible for detonating the devices via electronic messages and explosives implanted in them before they arrived in Lebanon, in line with theories that have circulated since the explosions.

The 15-member Security Council is due to meet on Friday over the blasts. Lebanese Prime Minister Najib Mikati called on the Security Council to take a firm stand to stop Israel's "aggression" and "technological war".

President Volodymyr Zelenskiy said on Wednesday that his "Victory Plan", intended to bring peace to Ukraine while keeping the country strong and avoiding all "frozen conflicts", was now complete after much consultation, Reuters reported.

Zelenskiy pledged last month to present his plan to U.S. President Joe Biden, presumably next week when he attends sessions of the U.N. Security Council and General Assembly.

While providing daily updates on the plan's preparation, Zelenskiy has given few clues of the contents, indicating only that it aims to create terms acceptable to Ukraine, now locked in conflict with Russia for more than 2-1/2 years.

"Today, it can be said that our victory plan is fully prepared. All the points, all key focus areas and all necessary detailed additions of the plan have been defined," Zelenskiy said in his nightly video address.

"The most important thing is the determination to implement it.

There was, Zelenskiy said, no alternative to peace, "no freezing of the war or any other manipulations that would simply postpone Russian aggression to another stage".

On Tuesday, the president said a meeting with top commanders had produced "good and strong content" in military terms, "precisely the kind that can significantly strengthen Ukraine".

Zelenskiy has used as the basis for negotiations a peace plan he presented in late 2022 calling for a withdrawal of all Russian troops, the restoration of Ukraine's post-Soviet borders and a means to bring Russia to account for its invasion, read the report.

The plan was the focal point of a "peace summit" hosted by Switzerland in June with participants pledging to convene a second summit later this year. Russia was not invited to the June summit and branded it as meaningless, though Ukraine and its allies say Moscow could attend the next gathering.

Zelenskiy has rejected any notion of negotiations while Russian troops occupy nearly 20% of the country's territory.

Russia has repeatedly said it is willing to negotiate, but rules out discussions while Ukrainian forces remain in its Kursk region after it launched an incursion into the area last month.

North Korea tested new tactical ballistic missiles using super-large warheads and modified cruise missiles on Wednesday as leader Kim Jong Un called for stronger conventional weapons and nuclear capabilities, state news agency KCNA reported.

The tests to improve weapons capabilities are required because of the grave threat posed by outside forces to the security of the country, Kim, who led the tests, was quoted as saying.

The account followed the firing of multiple short-range ballistic missiles on Wednesday reported by the South Korean military, which was the second time the North test-launched missiles in a week.

Last week, North Korea also unveiled a uranium enrichment facility, in its first such public report, Reuters reported.

Kim stressed "the need to continue to bolster up the nuclear force and have the strongest military technical capability and overwhelming offensive capability in the field of conventional weapons too," KCNA said.

Wednesday's tests involved the new tactical ballistic Hwasongpho-11-Da-4.5 missiles, KCNA said, indicating it was part of a series of short-range ballistic missiles it had been developing.

The missile was mounted with a 4.5-ton super-large conventional warhead, KCNA said.

North Korea's state media reported the tests of missiles with the same name in July, which was considered a partial success. On Thursday, state media released photographs of a projectile striking a target in a hilly area, read the report.

South Korea's military said on Thursday two ballistic missiles landed in a mountainous area in the North's northeast.

Such a missile launch test with an intention to hit an inland target is likely unprecedented, said Shin Seung-ki who is the head of research on North Korea's military at the state-run Korea Institute for Defense Analyses in Seoul.

North Korea routinely test-launches missiles to drop in the sea or on an uninhabited island.

The particular missile with the Hwasongpho-11-Da-4.5 designation is still under development but Russia may want it soon if its performance and reliability can be guaranteed through further testing, Shin said.

"North Korea will want to shorten that time as much as possible," he said.

Kyiv officials and independent experts have said there were signs some of the missiles used by Russia in the war against Ukraine were North Korean-made, including some that were produced this year. Moscow and Pyongyang both deny any illicit arms trade or shipments.

The North's military also tested a strategic cruise missile that has been upgraded for combat use, KCNA said.

North Korea has criticized military drills by the South Korean and U.S. militaries, including a large-scale exercise conducted this summer, as preparations for war on the Korean peninsula.

The allies say the drills are defensive in nature and aimed at maintaining readiness against any North Korean aggression.