GUATEMALA CITY, Sept 2 (Reuters) - Guatemalan President Alejandro Giammattei announced new national transport curbs and social restrictions on Thursday in an effort to contain a surge of coronavirus infections and relieve pressure on hospitals. Giammattei opted against the toughest lockdown measures but said from Saturday, auto transport will be prohibited for most trips from 8:00 p.m. to 4:00 a.m. and social gatherings such as weddings and public sports events will be banned for at least four weeks. The president, who is a medical doctor, said in a televised speech the measures were "urgent and necessary to contain the spread of the pandemic". "It will give our hospital system a chance to breath," he said, as the capital"s biggest hospital reported it could take no new patients due to the surge of COVID-19 cases. The new measures require the approval of Congress, which is expected to be granted on Friday. Guatemala, Central America"s biggest country with about 18 million residents, has posted nearly 480,000 coronavirus infections and more than 12,000 deaths, according to official data. To date, only 1.3 million Guatemalans have been fully vaccinated.