DERRY, N.H. — Sen. Marco Rubio is doubling his television advertising buy in South Carolina, his campaign confirmed Friday evening.

The Florida senator, rising in the polls in New Hampshire, which holds its Republican primary on Tuesday, is increasing his presidential campaign's investment in South Carolina from approximately $300,000 per week to about $600,000. The Republican primary in the Palmetto State is Feb. 20 and stands as a crucial contest for Rubio in his bid for the 2016 presidential nomination — if he can perform in New Hampshire.

The move comes just four days after the Rubio campaign chose not to move forward with a previously scheduled pre-order of additional television time in South Carolina, suggesting that it is optimistic about its prospects in the Granite State after finishing a surprisingly strong third in Iowa.

The Washington Examiner reported on Monday that the Rubio campaign chose not to move ahead with a pre-order of television advertising it had placed in July for an additional $500,000 in airtime. After reviewing total Palmetto State ad spending by other campaigns and super PACs, Rubio's campaign decided at the beginning of this week to hold steady in South Carolina at $300,000 per week and invest an additional $100,000 on television in New Hampshire.

On Friday, the campaign boosted its ad buy to $600,000 per week, just $200,000 off its original pre-buy of $800,000.