SEGA has said it is "reasonably encouraged" by the day one sales of Platinum Games' Vanquish, the new action title for PS3 and Xbox 360.

Vanquish launched last week in all territories.

"It's been in the marketplace for two days, we've seen the day one numbers and we're reasonably encouraged, but I think we need to see the rest of week one and probably week two just to see how it's going to play out," Mike Hayes, president and CEO of SEGA West told IGN.

Hayes was commenting on the sales in North America only.

Hayes added: "The challenge is that it's a new franchise and that it's releasing head-to-head with a lot of established franchises in the busiest time of the year."

According to SEGA Bits, Vanquish sold a combined 53,000 units on day one in Japan. UK sales aren't known, but the game did miss out on a Top 10 place, charting at No.12 in its debut week.

Compared to Platinum Games' previous release, Bayonetta, Vanquish appears to have had a sluggish start. The bewitching action title managed around 140,000 units on day one in Japan, entered the UK All Formats video game chart at No.5, but missed out on a Top 10 place in the US.

Bayonetta went on to sell over a million units worldwide.