Malawi's president has banned all exports of the food staple maize as well as fertilizer as the country gets to grips with the current food crisis.
Mutharika is asking citizens to contribute to a solidarity fund
"From today, no maize should be exported to other countries because we have to feed ourselves first," Bingu wa Mutharika said on Monday.
He said it did not make sense for Malawi - hit by one of its worst food shortages in years - to export maize.
At least 4.2m Malawians are in urgent need of food aid, according to the UN.
The president also ordered a ban of fertiliser exports, saying "we need it here for our food production".
There is a thriving unregulated trade of cheap Malawi maize and fertiliser in Zambia and Tanzania.
Merchants buy the products cheap in Malawi and export them to neighbouring countries.
Ironically, Malawian authorities buy the same maize at a higher price, especially in Tanzania.
"From today our borders are sealed," said Mr Mutharika, urging ordinary citizens to inspect trucks crossing borders and report suspicious exports.
He also announced a "Feed the Nation" initiative - a countrywide campaign to collect contribution in the form of money and food to feed the needy.
"I urge everyone to contribute at least 10% of their earnings to the initiative," he said.
Mr Mutharika, who donated 1m Malawi Kwacha (£5,000) to the initiative, said it was aimed at showing that Malawians can feed themselves before turning to international donors.
Malawi requires at least two million metric tons of maize to feed its 11 million citizens but, according to the Ministry of Agriculture, due to persistent drought, the country recorded a 24% drop in maize production.
The government has announced it will use $50m (£28m) to buy 300,000 tons of maize from South Africa.