BEIRUT -- Syria has announced that it is closing the two remaining land crossings into Lebanon as of midnight tonight, including the main Masnaa border crossing. According to LBC, Lebanese customs officials asked their Syrian counterparts at the border why, only to be told "it's a political decision." The crossing presumably will be closed indefinitely.

Masnaa is the busiest land crossing, sitting as it does on the road from Beirut to Damascus. It is one of Lebanon's main trade routes shipping its agricultural products to the rest of the Middle East and tonight's closures, following Syria's closure earlier this month of the northern border crossings because of the violence at Nahr el-Bared, leaves Lebanon with no land access to the outside world.

Syria has often used the border crossings to apply political pressure on Lebanon since the Feb. 14, 2005 assassination of former Prime Minister Rafik Hariri and the subsequent withdrawal of Syrian troops from Lebanon.

It could be a bit of a Syrian snit-fit in response to a delegation from the Arab League that is in town at the request of the anti-Syrian parliamentary majority. The anti-Syrian bloc is demanding Arab states intervene with Syria to stop its interference in Lebanese affairs and Damascus' alleged weapons smuggling to various armed groups.

Syria is feeling the heat from the imposition of the International tribunal under Chapter 7 of the UN charter earlier this month, and this will put the Lebanon pressure cooker under more pressure.