Israeli military intelligence and senior officials in the Mossad briefed a meeting of the nation's security cabinet that talks in Vienna between Iran and other world powers will lead to the U.S. returning to the 2015 nuclear deal, two officials who attended the meeting told me.

Why it matters: The Israeli government is very concerned about a U.S. return to the nuclear deal and is trying to convince the Biden administration not to take the pressure off the Iranian regime.

Iran on Friday started enriching uranium to 60% purity after the resumption of negotiations between the nation and other world powers in Vienna to restore the 2015 nuclear deal, Al Jazeera reports citing Iran's nuclear chief Ali Akbar Salehi.

Why it matters: The production news comes days after an apparent Israeli attack on Iran's Natanz uranium enrichment facility. It also pushes the country one step closer to producing weapons-grade uranium and is a severe violation of the nuclear deal.

Ongoing conflicts, economic crises and the fallout from COVID-19 will likely destabilize several countries in the Middle East in 2021 and could even put some on the brink of collapse, according to the U.S. intelligence community's annual Threat Assessment Report, released on Tuesday.

Why it matters: The report is the most comprehensive assessment the intelligence community produces every year. It paints a portrait of conflicts, insurgencies, terrorism and protest movements across the Middle East.

Iran has informed the director general of the International Atomic Energy Agency (IAEA) that it will begin 60% uranium enrichment, Deputy Foreign Minister Abbas Araghchi told reporters as he arrived to Vienna on Tuesday for a second round of nuclear talks.

Why it matters: This will be Iran's most severe violation of the 2015 nuclear deal since the Trump administration withdrew from the agreement in 2018. It's also a serious blow to the ongoing efforts to salvage the deal.

Iranian Foreign Minister Mohammad Javad Zarif has threatened retaliation against "any power with knowledge" of Sunday's attack on an Iranian nuclear site, and said Iran would now accelerate its violations of the 2015 nuclear deal until the U.S. lifts sanctions.

Why it matters: The apparent act of Israeli nuclear sabotage, which caused a blackout at the underground Natanz enrichment facility and may have caused significant damage, comes as the U.S. attempts to revive the nuclear deal.

Top national security officials from the U.S. and Israel will convene virtually on Tuesday for a second round of strategic talks on Iran, three Israeli officials tell me.

Why it matters: The talks come two days after an explosion at an Iranian nuclear facility that experts consider a likely act of Israeli sabotage, and one day before the U.S. resumes indirect nuclear talks in Vienna over a return to the 2015 nuclear deal — a prospect that has raised anxiety levels in Jerusalem.

The European Union imposed sanctions Monday against eight Iranian militia commanders and security officials, including the commander in chief of the Islamic Revolutionary Guard Corps (IRGC), over their role in a deadly crackdown on protests in 2019.

Why it matters: It's the first time the EU has sanctioned Iran for human rights abuses since 2013, and comes as the bloc looks to facilitate a U.S. return to the 2015 Iran nuclear deal.

The Biden administration says it had no role in the explosion on Sunday at an Iranian uranium enrichment facility. Iran has blamed Israel and vowed to take revenge.

Why it matters: The administration is attempting to negotiate a return to the 2015 Iran nuclear deal, with a second round of indirect talks set to start on Wednesday. The timing of the incident, along with several recent Israeli strikes on Iranian ships, could make Biden's diplomatic challenge more difficult.

Iran said Saturday it's testing a new and advanced nuclear centrifuge to more effectively enrich uranium, AP reports.

Why it matters: The announcement by Iranian President Hassan Rouhani comes as Tehran and Washington hold indirect talks in an attempt to bring the U.S. back into the 2015 nuclear deal.

This week's nuclear talks in Vienna "met expectations" but did not assuage U.S. doubts about Iran's willingness to negotiate in good faith over the 2015 nuclear deal, a senior State Department official told reporters on Friday.

The state of play: Iran refused to meet directly with the U.S. but held three days of talks with the nuclear deal's other signatories, while the U.S. — represented in Vienna by Iran envoy Rob Malley — communicated indirectly through envoys, primarily from the European Union.