b'28. Urges the least developed countries and their development partners to make use of existing initiatives and programmes, such as the relevant ministerial decisions of the World Trade Organization on duty-free and quota-free market access for the least developed countries and on preferential rules of origin for those countries, as well as aid for trade, reiterates its commitment to increasing aid-for-trade support, in particular for the least developed countries, striving to allocate an increasing proportion of aid for trade to the least developed countries, in accordance with development cooperation effectiveness principles, welcomes additional cooperation among developing countries to that end, and encourages the least developed countries to mainstream trade in their national development plans; '