File Photo: NATO Secretary-General Jens Stoltenberg. (Reuters)
NATO chief Jens Stoltenberg on Monday touched down in Ukraine on his first visit to the country hit by a separatist conflict that has caused the worst standoff between Moscow and the West since the Cold War.
Stoltenberg headed first to a military base in the western city of Lviv where the US army has been training Ukraine's forces.
Stoltenberg will meet Ukrainian President Petro Poroshenko there to launch civil emergency drills involving more than 1,000 rescue workers from 13 countries.
On Tuesday the NATO chief plans to attend a meeting of Ukraine's national security council.
NATO has been rattled by the crisis in Ukraine, where Moscow seized the Crimea peninsula in March 2014 and is accused of fuelling a separatist conflict.
Kiev sees Moscow's manoeuvring as revenge for its decisive shift towards the West following the ouster of Kremlin-backed president Viktor Yanukovych by mass protests.
Ex-Soviet Ukraine says it wants to join the US-led security bloc but NATO has been lukewarm on the proposal.
Any move by Ukraine towards NATO membership would stir ire in Moscow, which has accused the organisation of increasingly trying to hem it in following the collapse of the Soviet Union.
NATO has ratcheted up its activities in eastern Europe, rotating troops and equipment in its ex-Communist members to ease fears of Russian expansionism.
The visit of Stoltenberg is "a part of the policy that NATO has been following for a year and a half," a senior Ukrainian security official told AFP.
"They understand very well who is the aggressor and take appropriate measures."
The conflict between Ukraine's army and pro-Russian rebels in war-torn eastern Ukraine has killed nearly 8,000 people since April 2014.
A new ceasefire that came into force on September 1 has almost entirely stopped the fighting along the volatile frontline.
The Ukrainian security official said he expects the level of violence will remain low ahead of Russian President Vladimir Putin's highly-anticipated speech at the United Nations General Assembly on September 28, in which some observers suspect he will deflect attention from Ukraine onto the conflict in Syria.
"The truce will last at least until Putin's trip to the General Assembly," the official said, speaking on condition of anonymity.
"For a true solid lull, the Russian soldiers must leave" the territory of Ukraine, he added.
NATO and Kiev have repeatedly accused Russia of supporting separatist forces with arms and troops, allegations Moscow vehemently denies.