Lebanese troops are tightening security around the prime minister's office and other government buildings as a political crisis deepens over a U.N.-backed tribunal investigating the 2005 assassination of a former prime minister.
A senior security official confirms the security measures in and around Beirut stem from "concerns of movements on the ground by some parties."
The official spoke on condition of anonymity in line with regulations.
The Iranian-backed group Hezbollah toppled Western-backed Prime Minister Saad Hariri's government last week because of differences over the tribunal. Many expect Hezbollah to be indicted.
The new measures Thursday follow the departure from Beirut of Qatari and Turkish envoys who had been trying to mediate a solution to the crisis.