Secretary of State Antony Blinken on Friday said the U.S. had no involvement in Israel’s overnight airstrikes that reportedly hit a military base near the Iranian city of Isfahan. Mr. Blinken said at a press conference in Italy that the U.S. priority is de-escalation and “avoiding conflict.”

The reported Israeli strikes came less than a week after Iran on Saturday fired more than 300 missiles and drones at Israel, the vast majority of which were shot down by Israeli and U.S. defenses. Israel’s response seems to have been limited in scope, perhaps a sign that Israel and Iran want to pull back from the brink of war. 

In a separate development, however, Syrian state media said Israeli forces had also carried out a missile strike targeting an air defense unit in southern Syria. The area of Syria that was reportedly targeted is directly west of the Iranian city of Isfahan, some 930 miles away, and east of Israel.

The U.S. is accelerating work on its first new nuclear warhead in 40 years, but will do so without nuclear testing. The W93 warhead will be used on submarine-launched ballistic missiles and is “on track” for production beginning in the mid-2030s, according to Senate testimony this week by Energy Secretary Jennifer Granholm and National Nuclear Security Agency Administrator Jill Hruby.

The NNSA’s website indicates the W93 will include modern technologies, such as insensitive high explosives used for triggering. The warhead is said to be lighter than the current W76 and W88 warheads, allowing for greater missile ranges.

The department also is modernizing five existing warhead types — the B61-12 life extension program, the B61-13, the W88, W87 and W80 warheads. The B61 is a nuclear gravity bomb dropped by aircraft, and the newer variant will be built by 2025.

Efforts to restrict TikTok have a new ally in Senate Commerce Committee Chairwoman Maria Cantwell, who this week reversed her earlier resistance to legislation passed by the Republican-controlled House that would force the social media giant’s China-based owner, ByteDance, to sell TikTok or face a ban in the U.S.

National Security Tech Correspondent Ryan Lovelace has a deep dive explaining how the Washington Democrat’s shift on restricting TikTok follows other steps she has taken to change course on issues involving privacy and donations from Boeing. 

The development comes days after a former TikTok worker made headlines by stating the social media giant shares U.S. user data with counterparts in China via a stealth chain of command through which TikTok’s U.S.-based workforce answers to Chinese higher-ups. TikTok has long denied sharing data with the Chinese government.

The House passed the TikTok bill last month, but the legislation is stalled in the Senate. Ms. Cantwell’s new support for it could pave the way for Senate passage.

The Royal Australian Navy’s development of a massive “Ghost Shark” underwater drone is advancing ahead of schedule with help from the American defense tech company Anduril.

“Ghost Shark will provide [Australia’s] Navy with a stealthy, long-range autonomous undersea warfare capability that can conduct persistent intelligence, surveillance, reconnaissance and strike,” according to Asia-Pacific Defense Reporter. Insiders say it could transform the global naval warfare landscape over the coming years. It remains to be seen how the platform might intersect with U.S. naval operations.

“We have 42 Australian companies currently working on Ghost Shark, which is being designed, engineered and manufactured in Australia. We plan to manufacture at scale in Australia for the Royal Australian Navy, and then for export to our allies and partners around the world,” Shane Arnott, the senior vice president of engineering for Anduril Industries, said in a statement.

Russian President Vladimir Putin “never really left the KGB” and today “relies on his sycophantic security services and ruthless military to maintain his iron grip on the Kremlin,” writes Threat Status contributor Daniel N. Hoffman, a former CIA officer who once headed the agency’s Moscow station.

U.S. citizens are now caught in Mr. Putin’s crossfire. “For the first time since the Cold War, American citizens — even journalists — are no longer safe in Mr. Putin‘s Russia,” writes Mr. Hoffman, who cites the “growing list of unlawfully detained Americans, including schoolteacher Marc Fogel, Paul Whelan, Wall Street Journal reporter Evan Gershkovich, Ksenia Karelina and Radio Free Europe editor Alsu Kurmasheva.”

Mr. Putin would clearly like to engineer a trade, Mr. Hoffman writes, noting how Roger Carstens, the U.S. special presidential envoy for hostage affairs, said last week that he was drafting a new proposal designed to secure the release of Mr. Gershkovich and Mr. Whelan. “We should not, of course, expect a fair trade,” writes Mr. Hoffman, “because Mr. Putin has all the leverage of a dictator operating outside the rule of law.”

• April 19 — Iraq’s prime minister on building a stronger relationship with the U.S., Atlantic Council.

• April 19 — Cybersecurity in the Indo-Pacific: Japan, Center for a New American Security.

• April 19 — Toward reimagined global financial architecture: Progress and challenges, Brookings Institution.

• April 24 — Global Security Forum 2024: Gathering Strength in a Gathering Storm, Center for Strategic and International Studies.

• April 25 — Book Event: Tackling the China Challenge with Strength, Hudson Institute.