Updated 9.50am, adds President's statement
Prime Minister Robert Abela and PN leader Bernard Grech condemned the Russian aggression in Ukraine in separate statements on Thursday morning.
Ukraine came under Russian artillery fire and land invasion along its northern and southern borders on Thursday with Ukrainian forces returning fire.
Explosions were heard across the country after weeks of intense diplomacy and the imposition of Western sanctions on Russia failed to deter Putin, who had massed between 150,000 and 200,000 troops along the borders of Ukraine.
Abela said tension in Ukraine and intelligence on the possibility of a military attack had been persisting for a long time but the current scenes were heart-wrenching.
Attempts at an invasion in the eastern parts of the country were now moving closer to the capital and were unwanted.
He said that a diplomatic solution, safeguarding peace through dialogue was the preferred route and European leaders will be meeting in Brussels on Thursday to continue to express and show solidarity with Ukraine.
An EU summit on Thursday evening is scheduled to "discuss the crisis and further restrictive measures" that "will impose massive and severe consequences on Russia for its actions".
On his part, PN leader Bernard Grech said Russia's attack breached international treaties and the Ukrainian territorial integrity.
Malta, he said, had to fully support European efforts for a coordinated response through economic sanctions.
Grech said the Maltese and Europeans should be kept regularly updated on the EU-imposed sanctions and their effectiveness.
Grech said: "We are worried that the escalation of tensions will have impacts further away from the region. So coordination at a European level is required for such impacts to have the least possible effects on Maltese and European lives.
"This is a very ugly, delicate and threatening moment for the stability of Europe and beyond.
"As a country, we have to show solidarity with the people of Ukraine and, while observing our neutrality, spread the message that actions that place our country's integrity and sovereignty at risk are not acceptable."
Meanwhile, in another statement, ADPD called for the immediate suspension of the Individual Investor Programme.
"At this stage it is now clearer than ever that the programme poses a risk to our collective European security. It is not possible to know who is trying to take advantage of the terms of the scheme in order to put Europe at risk. I also call on the Malta Individual Investor Programme Agency to put all Maltese passports issued to holders of Russian passports under review and for details of such passport holders to be shared among the European security establishment as a matter of urgency, party chairman Carmel Cacopardo said.
He added “it is our collective duty to ensure that Malta is on the right side of history. We must not undermine the collective European response, which must be strong and proportionate. This is not the time for profit, but time to do the right thing."
The attacks on Ukraine were later also condemned by President George Vella, who expressed grave concern and conveyed support to the government and people of Ukraine.
"This escalation, and in particular the events that are being reported, represent a threat not only to the people of Ukraine but also for European and global stability," he said.
He joined other authorities and international actors in calling for an immediate cessation of hostilities, a withdrawal of military forces from Ukraine and for the full respect of Ukraine’s territorial integrity, sovereignty, and independence.
"All efforts should be made for restraint to prevail, for the full respect of international law, and to avert the real risk of further deterioration of the situation."