The United States has said it may give additional security assistance to Ukraine to help it combat "reckless and aggressive" behaviour from Russia, and urged Kiev not to waver in pursuing reforms and fighting corruption.
US secretary of state Antony Blinken met Ukrainian president Volodymyr Zelenskiy and other senior officials in Kiev on Thursday, as Nato warned that tens of thousands of Russian troops remained close to Ukraine's borders following recent drills that stoked fears of all-out war between the former allies.
“Russia has pulled back some forces, but significant forces remain at Ukraine’s border. Russia has pulled back some equipment, but significant equipment remains near Ukraine’s border. So Russia has the capacity, at fairly short notice, to take aggressive action if it so chooses,” Mr Blinken said.
“We are monitoring the situation very, very closely. And I can tell you, Mr President, that we stand strongly with you, partners do as well ... and we look to Russia to cease reckless and aggressive actions,” he told Mr Zelenskiy.
"We are actively looking at strengthening even further our security co-operation and security assistance," he added, saying that US president Joe Biden wanted to "reaffirm strongly our commitment to the partnership between our countries ... It was important as early as possible to say so in person."
Washington has given strong diplomatic and financial support to Ukraine since a 2014 revolution ousted its then Russian-backed leaders and tilted the country of 44 million towards the West.
Weapons supply
The US has also supplied weapons to Kiev and conducted training for government troops fighting Russian-led militants in Ukraine’s eastern Donbas region, where some 14,000 people have died in a seven-year conflict.
About 35 Ukrainian soldiers have been killed in clashes this year, and shelling and sniper fire intensified last month as Russia launched military exercises in which tens of thousands of troops and armoured vehicles, warships and attack aircraft moved towards Donbas and into Crimea, which Moscow annexed in 2014.
"We have seen some reduction in the number of Russian troops, but tens of thousands remain, and we are also seeing that Russia has kept a lot of weapons ... and equipment, and they're also imposing restrictions in the Black Sea," Nato secretary general Jens Stoltenberg said before a meeting of EU defence ministers.
“Overall, there is a significant Russian presence, and there are many more Russian troops now in and around Ukraine than before the recent increase in tensions.”
Mr Zelenskiy insisted that Ukraine was committed to a reform and anti-graft programme, despite slow progress, repeated setbacks and resistance from vested interests.
“Ukraine faces two challenges: one from outside, from Russia. In addition, there is a threat from within – it is corruption, oligarchs and others who put their interests above the interests of the Ukrainian people,” Mr Blinken said.
