A roadside bomb has exploded next to a United Nations convoy carrying French peacekeepers in south Lebanon, wounding five of them, the UN force said.
The bomb went off at the southern entrance of the port city of Sidon as a UN convoy with several vehicles was passing by.
It was not immediately clear who was behind the attack, but political tensions are rising in Lebanon over a UN-backed tribunal's indictment last month of four Hezbollah members in the 2005 assassination of former Lebanese Prime Minister Rafik Hariri.
Iranian-backed Hezbollah is the most powerful political and military force in Lebanon and it has refused to hand over the suspects. The tribunal is expected to publish details of the indictments after a 30-day deadline that expires at the end of the month.
There are also concerns that unrest in neighbouring Syria, which has seen more than four months of protests against the autocratic government there, could spill over into Lebanon.
UN peacekeepers have been deployed in southern Lebanon since 1978 to monitor the border with Israel. The force was boosted after Israel and Hezbollah fought a war in 2006 and now numbers close to 12,000.
There was a similar attack about two months ago, when a roadside bomb ripped through a UN convoy carrying Italian peacekeepers in southern Lebanon, wounding six. The May 28 attack was the first since 2008.
United Nations Interim Force in Lebanon spokesman Neeraj Singh said five peacekeepers were injured in the latest bombing and three went to a hospital. He did not say what nationality they were, but Lebanese security officials said they were French.
The officials said at least one of the wounded suffered injuries to the face and chest. The officials spoke on condition of anonymity in line with military regulations.
A police official said this bombing appeared to be smaller than the May blast. Both happened in the same area. He said preliminary investigations showed the bomb contained around two kilogrammes of explosive material.