
(This June 21 story corrects in paragraph 4 to show gas flows via Ukraine and Nord Stream 1 pipeline have fallen, removes reference to Russia cutting flows via Ukraine as act of retaliation)
KYIV (Reuters) - Russia warned Lithuania on Tuesday that it would face measures of a "serious negative impact" for blocking some shipments by rail to Moscow's Baltic Sea enclave of Kaliningrad, in its latest dispute over Western sanctions imposed on the country for the war in Ukraine.