Valmiki Ramayana Yuddha Kanda Sarga 30 Shloka 6

सम्भाषितुमपि even to converse, नशक्या not possible, अत्र there, सम्प्रश्न to question, नविद्यते not known, पन्था examine, सर्वत all over, पर्वतोपमै resembling mountains, वानरै Vanaras, रक्ष्यते guarded.

"It is not possible to converse with them or to question and or to examine, since they are guarded all over by mountains like Vanaras."