ADEISSEH, Lebanon â€” Lebanese and Israeli troops exchanged fire Tuesday in a fierce border battle that killed a senior Israeli officer, two Lebanese soldiers and a journalist â€” underlining how easily tensions can re-ignite along the frontier where Israel and Hezbollah fought a war four years ago. It was the worst fighting since 2006 in the area, where Israeli and Lebanese soldiers patrol within shouting distance of each other, separated by the U.N.-drawn Blue Line boundary. The fighting flared into Israeli tank, helicopter and artillery strikes near this Lebanese town, but ended after several hours and there was no sign that either side was preparing to escalate. The Shiite guerrilla force Hezbollah said it offered to help the Lebanese army but in the end did not get involved. “We told our brothers, control yourselves and don’t do anything,” Hezbollah leader Sheik Hassan Nasrallah in a televised speech. But, he warned, his fighters would intervene if Israeli troops ever attack Lebanese forces again. “Any Israeli arm extended against the Lebanese military will be cut off by the resistance,” said Nasrallah, whose arsenal is far more powerful than the Lebanese army’s.