Prime Minister Mariano Rajoy has tweeted a video clip of himself working out on a gym treadmill a day after he was punched in the head by a youth during an election campaign appearance.

Rajoy, 60, said in his tweet accompanying the video, "Happy Thursday from Barcelona. We continue heading forward."

Rajoy was assaulted Wednesday evening in the northwestern town of Pontevedra as he walked among a crowd during a campaign appearance for Sunday's general election,

Spanish TV images showed Rajoy falling toward the ground from the impact but being propped up by people around him.

Leaders of other parties contesting the election condemned the assault.

Polls suggest that Rajoy's Popular Party will win the most seats but fall way short of the majority it has in parliament since 2011.