Lisbon is to dispatch "vests, helmets, night-vision goggles, grenades and ammunition of various calibres", the ministry said in a statement in the early hours on Twitter.

"Portugal supports Ukraine, which is defending itself against an unjustified, illegal and unacceptable invasion," Defence Minister Joao Cravinho said in another tweet.

Foreign Minister Augusto Santos Silva on Saturday told CNN Portugal that was "totally open" to welcoming "thousands of Ukrainians" forced to flee their country.

He also said Lisbon had suspended the review of Russia applications for so-called "golden visas", residency permits given to wealthy foreign investors.

A protest in solidarity with Ukraine is to be held later in the day in the capital Lisbon, after a previous gathering of hundreds of people on Saturday.

Greece on Sunday also said it would send "defence equipment" to Ukraine via Poland, without providing further details of what it would be.

Germany said Saturday its army would transfer 1,000 anti-tank weapons and 500 Stinger-class surface-to-air missiles to Ukraine, in a U-turn from its longstanding policy of banning weapon exports to conflict zones.

The Netherlands, France, Belgium, and the Czech Republic have also pledged various kinds of weaponry, while the United States is providing Ukraine with $350 million in additional military equipment.