DigitalGlobe imagery of North Korea's 5MWe Reactor at the Yongbyon nuclear site. File photo: DigitalGlobe/Institute for Science and International Security via Getty Images

Satellite images of North Korea’s main nuclear site show railcar activity that could be associated with the reprocessing of radioactive material into bomb fuel, the Center for Strategic and International Studies said Tuesday.

"In the past these specialized railcars appear to have been associated with the movement of radioactive material or reprocessing campaigns. The current activity, along with their configurations, does not rule out their possible involvement in such activity, either before or after a reprocessing campaign."

Why it matters: The activity signs at Yongbyon nuclear site on April 12 come at a delicate time in negotiations between the U.S. and North Korea. President Trump's February summit with North Korean leader Kim Jong-un ended abruptly over a disagreement about the nuclear facility and sanctions.

Between the lines: Secretary of State Mike Pompeo hasn't ruled out a third summit taking place between Trump and Kim. Pompeo said Monday there are "lots of conversations taking place" and Trump is "determined to move forward diplomatically." He said Kim had repeatedly pledged a commitment to denuclearize.

"We collectively need to see that outcome move forward. And we’re working – our teams are working with the North Koreans to plot a – to chart a path forward so that we can get there. He said he wanted it done by the end of the year. I’d love to see that done sooner."

Go deeper

Updated 52 mins ago - Politics & Policy

Coronavirus dashboard

Illustration: Sarah Grillo/Axios

  1. Global: Total confirmed cases as of 8 a.m. ET: 19,401,935 — Total deaths: 721,906 — Total recoveries — 11,767,805Map.
  2. U.S.: Total confirmed cases as of 8 a.m. ET: 4,942,747 — Total deaths: 161,367 — Total recoveries: 1,623,870 — Total tests: 60,415,558Map.
  3. Politics: Trump says he's prepared to sign executive orders on coronavirus aid.
  4. Education: Cuomo says all New York schools can reopen for in-person learning.
  5. Public health: Surgeon general urges flu shots to prevent "double whammy" with coronavirus — Massachusetts pauses reopening after uptick in coronavirus cases.
  6. World: Africa records over 1 million coronavirus cases — Gates Foundation puts $150 million behind coronavirus vaccine production.

The silver linings of online school

Illustration: Annelise Capossela/Axios

Online learning can be frustrating for students, teachers and parents, but some methods are working.

The big picture: Just as companies are using this era of telework to try new things, some principals, teachers and education startups are treating remote learning as a period of experimentation, too.

Warren and Clinton to speak on same night of Democratic convention

(Photos: Abdulhamid Hosbas/Anadolu Agency via Getty Images, Sean Rayford/Getty Images)

Sen. Elizabeth Warren and Hillary Clinton both are slated to speak on the Wednesday of the Democratic convention — Aug. 19 — four sources familiar with the planning told Axios.

Why it matters: That's the same night Joe Biden's running mate (to be revealed next week) will address the nation. Clinton and Warren represent two of the most influential wise-women of Democratic politics with the potential to turn out millions of establishment and progressive voters in November.