The 10 most important things in the world right now

Hello! Here's what you need to know for Tuesday.

1. Ukrainian President Petro Poroshenko said pro-Russian rebels have pulled back a large amount of heavy weapons in the contested eastern region, as part of a ceasefire deal reached in February.

2. Two helicopters collided in Argentina on Monday, killing 10 people, including three well-known French athletes.

3. Greece's new radical government said talks with its eurozone partners Monday on extending financial aid had a "positive" outcome.

4. Forty-seven US Republican senators sent an open letter to Iran's leaders warning about a nuclear deal with President Barack Obama.

5. Apple revealed Monday that the high-anticipated Apple Watch will officially launch on April 24 and come in three distinct styles.

6. New Zealand police said anonymous letters were sent in November threatening to poison the country's infant formula if the use of poison on pests, like rats and possums, wasn't stopped by March.

7. Japan's weather bureau raised the possibility of El Nino emerging by summer, a weather pattern that is usually linked to heavy rainfall in some regions and drought in others.

8. Two 600-foot ships collided in Houston, Texas, causing a leak of flammable liquid.

9. The CEO of Credit Suisse, Brady Dougan, is reportedly stepping down.

10. The owners of an Irish Setter who died after winning Britain's Crufts dog show claim their dog was poisoned.

And finally ...

Margaret Thatcher's private armoured bus is on sale for £25,000.