Arthashastra
दुर्गं राष्ट्रं स्कन्ध आवारं वा अस्य गूढाः शस्त्र रस अग्निभिः साधयेयुः ॥
Spies, under concealment, may capture the enemy's fort, country, or camp with the aid of weapons, poison, or fire.
english translation
durgaM rASTraM skandha AvAraM vA asya gUDhAH zastra rasa agnibhiH sAdhayeyuH ॥
hk transliteration by Sanscript