NATO chief Mark Rutte has asked allies to devote 0.25 percent of GDP to Ukraine as he seeks to ease growing tensions within the alliance over aid to Kyiv. But the proposal — which could unlock tens of billions of dollars in additional aid — is already running into stiff resistance from some major NATO members. The alliance's secretary-general raised the possibility at a closed-door meeting of NATO ambassadors late last month, said two alliance diplomats and a person familiar with the matter,