Brussels, Mar 25 (IANS): The North Atlantic Treaty Organisation (NATO) has approved the deployment of four new battle groups in the eastern part of the alliance, including Bulgaria, Hungary, Romania and Slovakia, declared Jens Stoltenberg, NATO's Secretary General during a press briefing.

The four new battle groups deployed along eastern part of the NATO alliance were approved on Thursday, Xinhua news agency reported.

In total, there will now be eight NATO battle groups deployed along the eastern flank of the alliance, from the Baltic Sea to the Black Sea.

The organisation's heads of states were called for an extraordinary meeting to discuss further support for Ukraine, in the context of the Russia-Ukraine conflict that started in February.

Meanwhile, Stoltenberg said the alliance's top military commander has activated NATO's chemical, biological, radiological and nuclear defense elements and allies are deploying additional chemical and biological and nuclear defenses.