Vladimir Putin has been sworn in for another six years as Russian President, buoyed by popular support but weighed down too by a costly confrontation with the West, a fragile economy and uncertainty about what happens when his term ends.

At least 10 people are killed and 50 injured in an explosion on a train carriage in St Petersburg's underground metro, Russian authorities say.

Israel could respond to any Iranian attack on it from Syria by toppling president Bashar al-Assad's government, an Israeli security cabinet minister says, hinting that Mr Assad himself may be targeted for assassination.

Russians take to the streets in more than 90 towns and cities across the country to register their opposition to Vladimir Putin's presidential inauguration that will take place next week.

The New York Post's news app is hacked on April Fools' Day, sending out a series of unusual push alerts including Nirvana lyrics and a message reading "Heil President Donald Trump".