Egypt delayed the potential vote at the Security Council, putting off a potential standoff between the US and Israel. An Israeli official later tells CNN his country reached out to Trump for help in pressuring the Obama administration.

“The resolution being considered at the United Nations Security Council regarding Israel should be vetoed,” Trump tweets, linking to a statement.

WHAT HAPPENED: Trump pressures the Obama administration to veto a UN Security Council resolution condemning settlement activity, an unprecedented move by a President-elect who has not yet moved into the White House.

In the span of just a few hours, Trump shook international relations by undercutting the Obama administration over a UN resolution on Israeli settlements , indicated he would ramp up nuclear competition with Russia and then jolted a major defense contractor — and its shareholders — by suggesting he would ask Boeing to replace a fighter jet being made by Lockheed Martin.

President-elect Donald Trump long ago earned a reputation for being unpredictable in his statements, but he outdid himself on Thursday.

WHAT FOLLOWED: On sensitive issues of diplomacy and national security, Trump has displayed a continued willingness to pressure and contradict President Barack Obama, eschewing a “one president at a time” policy that Obama insists must govern the peaceful transition of power.

Official: Israel turns to Trump for UN help 02:17

Nuclear arms

THE TIME: 11:50 a.m. ET

WHAT HAPPENED: Trump threatens a nuclear arms race.

“The United States must greatly strengthen and expand its nuclear capability until such time as the world comes to its senses regarding nukes,” Trump tweets.

Hours earlier in Moscow, Russian President Vladimir Putin said in a defense speech in Moscow that Russia needs to “enhance the combat capability of strategic nuclear forces, primarily by strengthening missile complexes that will be guaranteed to penetrate existing and future missile defense systems.”

WHAT FOLLOWED: The exchange appeared to raise the prospect of a new arms race between the US and Russia, which between them boast more than 14,000 nuclear warheads, the still deadly legacy of their four-decades long Cold War standoff.

Boeing vs. Lockheed Martin

THE TIME: 5:26 p.m. ET

WHAT HAPPENED: Trump cost millions in market value to Lockheed Martin and caused thousands of people to now worry they may lose their jobs after tweeting that the Pentagon’s costly new F-35 Joint Strike Fighter could be replaced with a modified version of a less expensive plane, the F/A-18 Super Hornet.

The F-35 is made by Lockheed Martin, while the Super Hornet is made by aerospace rival Boeing.

“Based on the tremendous cost and cost overruns of the Lockheed Martin F-35, I have asked Boeing to price-out a comparable F-18 Super Hornet!,” Trump tweets.