QUITO, May 1 (Xinhua) -- Ecuador on Friday began imposing a 100 percent tariff on all imports from Colombia, escalating trade tensions between the two countries, authorities said.

The measure applies to all goods of Colombian origin or shipped from Colombia, based on their customs value.

Authorities said the move is aimed at strengthening border security and customs controls.

However, exceptions include strategic sectors such as oil and energy, as well as special regimes like temporary admission, customs transit and re-export. Private tourist vehicles are also excluded.

The tariff, described as a "security surcharge," has been gradually increased in recent months, rising from 30 percent in February to 50 percent in March.

Business groups have warned the measure could disrupt supply chains, affect trade flows and impact employment.

Local media reported that border cities such as Tulcan in Ecuador and Ipiales in Colombia are particularly vulnerable, given their reliance on cross-border trade, which moves more than 500,000 tonnes of goods annually by land.

Analysts say the policy shift adds uncertainty to bilateral relations and economic activity in the border region. ■