A Tory former minister has said it would be “a brazen act of war” if Russia was behind an attack on a Russian ex-spy.
Sir Edward Leigh said the circumstantial evidence was “very strong” against Russia over the incident in Salisbury, adding that it was an attempt at “humiliating our country”.
Labour former minister Ben Bradshaw also spoke out about the growing threat “of the terrorist Russia state under President Putin”.
Sir Edward said: “The circumstantial evidence against Russia is very strong. Who else would have the motive and the means?
“Can I put the same question to the Home Secretary as I put to the Foreign Secretary earlier this week?
“Those of us who seek to understand Russia know that the only way to preserve peace is through strength.
“If Russia is behind this, this is a brazen act of war, of humiliating our country.”
He went on to urge Ms Rudd to support calls from defence minister Tobias Ellwood and invest more resources in defence.
“There will come a time for attribution and there will be, then, consequences and there will be further information that follows.
“But now, I’m concerned about the incident and the consequences around that.”
Mr Bradshaw sought assurance that the Government would take “meaningful action” to tackle the threat from Russia.
He added: “There are many members on both sides of this House who have warned for several years about the growing threat of the terrorist Russia state under President Putin, whether it’s money laundering in the city of London, the targeted murders and the interference in our political and democratic system.”
Ms Rudd said: “This Government has not been asleep at the switch in terms of where our international enemies are.
“He refers to Russia and separately to this incident I would say that we have been very clear about our disagreements with Russia, particularly on Ukraine and Syria and we have been outspoken in our criticism and determination to take action.
She added: “We will go further, should there be the need to do so.”
Ms Cooper, the chairwoman of the Home Affairs select committee, also suggested the Home Secretary consider going to the UN Security Council and asking for a statement from all nations to provide assistance, including a willingness to extradite suspects.
Ms Rudd said: “I have got her letter and I will be responding, but I would just gently say that now is not the time to investigate what is actually only, at the moment, rumour and speculation.
“Now is the time to focus on the incident at hand and the investigation proceeding.
“She makers a suggestion regarding international activity and I can just say to her that at some stage, we will be coming back to the House with our proposals.
“But for now, we are merely preparing and concentrating on the incident.”