Worsening congestion at Nigeria's major ports is crippling the economy of the West African sub-region. Manufacturers say essential cargoes are stranded at the ports and their factories are on the brink of closing down, as a standoff between importers and the government showed no signs of easing. "A number of those containers that have been out there for weeks contain industrial raw material," an industry source said. Prices of manufactured goods in Nigeria and in the sub-region are reported to have increased noticeably, some goods by as much as 35 percent since the problems at the ports began three weeks ago. Officials of the Manufacturers Association of Nigeria (MAN) said they would comment on the situation after a meeting in southeast Nigeria later on Thursday.