Ukraine: 3/2 morning update

The BBC reports on the latest in the mobilization in Ukraine.

Ukraine has ordered a full military mobilisation in response to Russia's build-up of its forces in Crimea.

Prime Minster Arseniy Yatsenyuk said the country was "on the brink of disaster".

US President Barack Obama has called Russian troop deployments a "violation of Ukrainian sovereignty".

Nato is conducting emergency talks on the crisis. Its secretary-general has said Russia's actions "threatened peace and security in Europe".

Several other measures were announced on Sunday by national security officials:

The armed forces would be put on "full combat readiness".

• Reserves to be mobilised and trained
• Ukraine's foreign minister will seek the help of US and UK leaders in guaranteeing its security
• Emergency headquarters to be set up
• Increased security at key sites, including nuclear plants.
• Airspace closed to all non-civilian aircraft.

The BBC has seen what appear to be Russian troops digging trenches on the Crimean border.