People in Spain will only be allowed to leave their homes to buy food and medicine, commute to work, or go to provide care.
France has shut down most shops, restaurants and entertainment facilities - including ski resorts - from midnight on Saturday as part of measures to contain the spread of COVID-19, which has claimed 91 lives in the country.
Almost 4,500 people have now tested positive for coronavirus in France, with 300 in intensive care, according to Jerome Salomon, head of the French public health authority.
Exceptions on the shop ban will include food stores, pharmacies and petrol stations, French prime minister Edouard Philippe told reporters.
Spanish Prime Minister Pedro Sanchez confirmed his government is to impose tight movement restrictions on its 47 million citizens as part of a 15-day state of emergency, beginning immediately.
He said the coronavirus crisis required "extraordinary decisions" and would have a "big economic impact".
The interior ministry will be in control of all police forces, and the armed forces will be on standby.
There have been nearly 6,400 cases and 196 deaths in Spain - a big rise from the 120 deaths reported on Friday, public broadcaster TVE said.
Spain is also closing all schools, universities, restaurants, bars and hotels nationwide along with non-essential stores - a move some of the hardest-hit communities have already carried out.
In response, Jet2 planes heading to Spain turned back mid-flight on Saturday morning after the low-cost airline announced the cancellation of flights to the country, as well as the Balearic and the Canary Islands.
Travel company TUI has cancelled holidays booked to Spain this weekend.
Italy remains the worst affected country in Europe and second only to China, where the highly infectious virus first emerged.
The number of deaths linked to the outbreak has risen to 1,441, up from 1,266 a day earlier, while confirmed cases soared by nearly 3,500 - a fifth - to more than 21,100.
Greece has banned all flights still operating to and from Italy after reporting two more deaths, raising the total to three. The number of cases has reached 228.
The Swedish government is advising its citizens against all unnecessary trips abroad, while Lithuania is closing its borders to almost all foreigners from midnight on Monday.
The World Health Organisation says Europe has become the epicentre of the pandemic.
Morocco has suspended flights to and from 21 countries including Egypt, Bahrain, United Arab Emirates, Greece, Norway, Sweden, Switzerland and Senegal, its state news agency reported.
