Good Morning Australia!! - Trump threatens an important anti-nuclear treaty - No one is satisfied with the Saudi story of Jamal Khashoggi's death - What's up with that migrant caravan heading to the US? - And more in your CareerSpot Global News Briefs:

Russian officials are lashing out at Donald Trump's threat to pull out of a key arms control treaty.  The Intermediate-Range Nuclear Forces (INF) treaty, signed by then-president Ronald Reagan and the final Soviet leader Mikhail Gorbachev, has kept medium-range nukes out of Europe since 1987.  But Trump is accusing Russia of violating the treaty first and told reporters on Saturday that the US would "have to develop those weapons" in response.  "This would be a very dangerous step that, I'm sure, not only will not be comprehended by the international community but will provoke serious condemnation," said Russia's Deputy Foreign Minister Sergei Ryabkov.  Even Gorbachev himself spoke out, saying Trump's action is "not the work of a great mind", and that withdrawal "would undermine all the efforts made by the leaders of the USSR and the USA to achieve nuclear disarmament".

The Saudi explanation for the death of dissident journalist Jamal Khashoggi is not catching on.  The UK, France, and Germany are demanding that Riyadh clarify its comments; they issued a joint statement saying that any claim that the prominent critic of Crown prince Muhammad bin Salman (MBS) died in a "fist fight" in the consulate in Istanbul needed "to be backed by facts to be considered credible"; it continued, "Nothing can justify this killing and we condemn it in the strongest possible terms."  Turkey says a Saudi hit team was waiting inside the consulate, abducting Khashoggi and torturing him to death in a grueling seven-minute ordeal.  Turkish President Recep Tayyip Erdogan says he'll release more of his investigators' information on Tuesday.

A march of thousands of Central American migrants is continuing north towards the US border with Mexico.  Much of the group has passed over Mexico's southern border, despite attempts to keep them out.  It's not clear who organized this, or why, or why at this time - just weeks before a major US election, providing confirmation bias to US conservative voters who rightly-or-wrongly believe their borders are under threat.

Sunday's regional elections were the Polish peoples' first chance to render a verdict on the divisive rule of the far-right Law and Justice (PiS) party, and that verdict is mixed.  Technically, PiS won with the most votes.  But this year's 32.3 percent is worse than the 37.6 percent it won in 2015 parliamentary elections.  And PiS couldn't claim the cherry on top of the sundae, the Warsaw mayor's race:  That went to Rafal Trzaskowski of the center-right Civic Platform (CO) with 54.1 percent of the vote, about 24 points in front of his pugnacious PiS rival.

An express train derailed in northern Taiwan, killing at least 22 people and injuring at least 160 others.  The Puyama express 6432 service was travelling between Taipei and the eastern county of Taitung when all eight of its carriages derailed close to Xinma station, near the town of Su'ao.  This was a relatively new train on an updated line that was popular for weekend travel.  The cause is under investigation.

China says the top representative governing the Chinese territory of Macau has died after falling from the high rise building where he lived.  A statement from Beijing said that 59-year old Zheng Xiaosong had been suffering from depression, implying he had killed himself.  There is no indication that he had run afoul of the country's anti-corruption investigators.

Christians and Muslims battled at a marketplace in central Nigeria's Kaduna state, resulting in at least 55 deaths.  President Muhammadu Buhari condemned the violence, saying:  "No culture and religion support the disregard for the sanctity of life," adding that "peaceful coexistence is necessary for the progress of any society and its well-being".  This started with a clash between wheelbarrow porters in the town of Kasuwan Magani and quickly broke down along religious lines.