UNITED NATIONS, Dec. 19 (Xinhua) -- UN Undersecretary-General for Peacekeeping Operations Jean-Pierre Lacroix on Wednesday warned of the risk of miscalculation on the border between Israel and Lebanon with the discovery of tunnels from Lebanon into Israel.

"I commend both the Israel Defense Forces (IDF) and the Lebanese Armed Forces for their stated commitment ... and their intention to maintain the prevailing calm along the Blue Line and avoid any escalation. The potential for miscalculation, however, cannot be underestimated," Lacroix told the Security Council.

"The parties have been reminded that provocative activities along the Blue Line and heightened rhetoric contribute to an environment of increased risk."

Since the discovery of tunnels and the IDF's operation to disable them, the United Nations Interim Force in Lebanon (UNIFIL) has confirmed the existence of four tunnels south of the Blue Line, said Lacroix.

UNIFIL technical assessments have further determined that at least two of these tunnels cross the Blue Line and constitute violations of UN Security Council Resolution 1701, he said.

A thorough investigation to establish the trajectories and points of origin of the identified tunnels is a complex task. The tunnels are between 29 and 46 meters below ground, difficult to detect and in close proximity to areas sensitive to both parties, said the UN peacekeeping chief.

While they are a serious violation of Resolution 1701, the tunnels do not appear thus far to have exit points on the Israeli side, he said.

UNIFIL is acting judiciously to complete its investigations of the tunnels -- with technical teams on the ground -- and to work with both Israel and Lebanon to ensure that any tunnels that are in violation of Resolution 1701 are disabled decisively and safely, said Lacroix.

"This is a matter of serious concern. The United Nations, including this Headquarters (in New York), has requested the Lebanese authorities to ensure urgent follow-up actions in accordance with the responsibilities of the government of Lebanon pursuant to Resolution 1701. UNIFIL has requested the Lebanese authorities to work with the mission to identify and disable any tunnels crossing the Blue Line from Lebanon in violation of Resolution 1701."

UNIFIL has deployed additional troops and liaison teams to sensitive locations along the Blue Line. UNIFIL will continue to assist the parties to maintain calm and meet their obligations under Resolution 1701, he said.

The Blue Line is a border demarcation between Lebanon and Israel published by the United Nations in 2000.