Ukraine on Friday accused Moscow of invading after Russia sent the first part of its aid convoy into east Ukraine.

Ukraine on Friday accused Moscow of invading after Russia sent the first part of its aid convoy into east Ukraine.

Moscow called week-long delays in allowing the vehicles across the border an "outrage" as it ordered the convoy into territory held by pro-federalization, despite Red Cross officials refusing to provide and escort because of security concerns.

"This is a direct invasion," the head of Ukraine's security service, Valentyn Nalyvaychenko, was quoted by news agencies as saying.

Ukraine said all responsibility for the trucks' safety lay with Moscow, after Russia warned "against any attempts to disrupt a totally humanitarian mission."

"The responsibility for any possible consequences of provocations against the humanitarian convoy lie completely with those who are ready to continue to sacrifice human lives for their ambitions and geopolitical plans," the Russian foreign ministry said in a statement.

Russia has been haggling with Ukraine over the convoy, with Kiev claiming that the lorries could be used to bolster pro-federalization movement or provide a pretext for Russia to send in troops.

However, Moscow insists it just wants to get urgently needed assistance to residents in the stricken region who have been without water and electricity for weeks.

Moscow said it was ready to have Red Cross officials accompany the convoy, but the organization said it had backed out of the operation because of fierce fighting raging in the area where the trucks are heading.