Fleeing Idlib. Photo: Rami Al Sayed/AFP via Getty Images

Bashar al-Assad’s Russia-backed offensive on Syria's northwestern enclave of Idlib — home to the last rebel-held areas — has forced some 150,000 civilians to flee over the past two weeks and led to direct clashes with Turkey.

Why it matters: David Miliband, CEO of the International Rescue Committee, tells Axios that the future of Idlib is being decided by an “arm wrestle between the Russians and the Turks” with “no U.S. engagement” and massive humanitarian consequences.

  • Turkey, which supported the rebels against Assad, announced earlier this week that eight of its forces had been killed by shelling in Idlib. It claimed to have "neutralized" 76 Syrian troops in response.
  • Turkish President Recep Tayyip Erdoğan has reserved some of his ire for Assad's patron, Russia. Turkey and Russia have inched closer together in recent years but stand on opposite sides in Syria as well as Libya.
  • Erdoğan fears yet another mass exodus of refugees to Turkey, which already hosts more than 3 million Syrians.

What to watch: In northeast Syria, meanwhile, there have been a series of “potentially dangerous standoffs” between Russian contractors and U.S. troops, per WSJ. U.S. envoy James Jeffrey says Russia is attempting to “challenge our presence in the northeast.”

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Arrest over letter to Trump containing poison ricin

President Trump returning to the White House from Minnesota on Sept. 18. Photo: Win McNamee/Getty Images

A suspect was arrested for allegedly "sending a suspicious letter" after law enforcement agents intercepted an envelope addressed to President Trump containing the poison ricin, the FBI confirmed in an emailed statement to Axios Sunday.

Details: The suspect, a woman, was arrested while trying to enter New York from Canada, law enforcement forces said.

Updated 2 hours ago - Politics & Policy

Coronavirus dashboard

Illustration: Sarah Grillo/Axios

  1. Global: Total confirmed cases as of 7 p.m. ET: 30,881,522 — Total deaths: 958,493— Total recoveries: 21,119,006Map.
  2. U.S.: Total confirmed cases as of 7 p.m. ET: 6,794,479 — Total deaths: 199,469 — Total recoveries: 2,590,671 — Total tests: 95,108,559Map.
  3. Politics: Testing czar on Trump's CDC contradictions: "Everybody is right" Ex-FDA chief: Career scientists won't be "easily cowed" by political vaccine pressure.
  4. Education: What we overlooked in the switch to remote learning.
  5. Health: The dwindling chances of eliminating COVID-19 — 7 states set single-day coronavirus case records last week.
  6. World: England sets £10,000 fine for breaking self-isolation rules — The countries painting their pandemic recoveries green.

Trump campaign goes all in on Pennsylvania

Trump poster in Scranton, Pennsylvania. Photo: Robert Nickelsberg/Getty Images

The president's campaign is placing more importance on Pennsylvania amid growing concern that his chances of clinching Wisconsin are slipping, Trump campaign sources tell Axios.

Driving the news: Pennsylvania, which has 20 electoral votes, twice Wisconsin's number, actually has been trending higher in recent public and internal polling, a welcome development for the campaign.