Quotients of Free pro-p groups

Question

Let $P_n$ denote the pro-$p$ completion of $F_n$ the free group of rank $n$. Given a (abstract) group homomorphism
$$ \phi:P_n\rightarrow G $$
where $G$ is a discrete group. Is $\phi$ continuous?

The case $G$ is finite is a Theorem of Serre and $\phi$ is continuous in this case.

Answer 1

Not in general. Consider for instance the case that $G$ is the same abstract group as $P_n$, but with the discrete topology.

If $G$ is finitely generated, the answer is yes. See this article of Nikolov and Segal: http://arxiv.org/abs/1102.3037