Ukrainian President Petro Poroshenko has signed a decree imposing martial law fewer than 24 hours after Russian servicemen opened fire on three Ukrainian ships near Crimea, wounding six servicemen and escalating a months-old naval confrontation that could reignite Europe's hottest armed conflict. Poroshenko has ordered for an emergency session of Verkhovna Rada, Ukraine's lower house of parliament, to take place later on Monday during which legislators will vote on the decree. If approved, as expected, the law will be imposed for 30 days from Wednesday onwards. Poroshenko initially proposed rolling out the decree for a 60 day period, but halved the proposed timeframe ahead of Monday's parliamentary session and ruled out any delay to elections scheduled to take place early next year during a televised address. He also declared the decree would not include any restrictions on citizens' rights. Al Jazeera's Rory Challands reports from Moscow. Subscribe to our channel: http://aje.io/AJSubscribe Follow us on Twitter: / ajenglish Find us on Facebook: / aljazeera Check our website: https://www.aljazeera.com/ #AlJazeeraEnglish #Ukraine #Crimea