There have been "some worrying signs of stepping up levels of activity both by Russian forces and by Russian-controlled separatist forces” in Ukraine, Hammond told the BBC's Andrew Marr.
There have been media reports in the last week that Washington was considering withdrawing from a Cold War-era treaty with Moscow and returning nuclear-capable medium-range missiles to Europe in an effort to counter what it calls "Russian aggression."
When asked if the UK would host American nukes, Hammond said: "That would be a decision that we would make together if that proposition was on the table. We would look at all the pros and the cons and come to a conclusion.”
What Hammond is particularly worried about is Russia's "asymmetric warfare doctrine," which he says, includes alleged use of "deniable proxies" and the stationing of missiles in the coastal exclave of Kaliningrad between Poland and Lithuania.
According to Hammond, Russia needs to get "a clear signal" that "we will not allow them to transgress our red lines." Asked whether he thinks stationing US nuclear weapons would be that signal, he said: "It could be, but I think we have got a very delicate act to perform here."
Despite all its alleged aggression, Russia according to Hammond has "a sense of being surrounded and under attack," and he would not want "to make unnecessary provocations."
In any case, UK hosting US nukes remains a distant prospect so far, as the foreign secretary said he hasn't seen "a detailed case for it."
The UK has its own nuclear arsenal in the Trident program. It comprises about 200 warheads based on several submarines stationed at a base in Scotland. Recent plans to modernize the arsenal have been met with mass protests.
Moscow warned that possible redeployment of US nuclear cruise missiles to Europe would only add to existing tensions, instead of increasing America's security. It is accusing Washington of violating the 1987 INF treaty and waging an information war in an effort to discredit Russia at all costs.