Colombia's benchmark stock index climbed Monday, pushed higher by key oil stocks, while the peso weakened slightly against the dollar.

The IGBC index, which encompasses Colombia's blue-chip stocks, rose 1.78%, to 15008.36 points. Pacific Rubiales Energy (PRE.T, PEGFF), an oil firm listed in Toronto and Bogota, rose 2.32%, to COP63,640. Colombia's state-run oil firm Ecopetrol SA (EC, ECOPETROL.BO) climbed 0.25%, to COP3,965.00.

The Colombian peso weakened against the dollar to close at COP1,907.10, from COP1,906.00 Friday, leaving it just a few ticks from its weakest level of the year, COP1,910.00, which was set last week.

The central bank, after a policy meeting Friday, said it would continue through at least June 17 to buy at least $20 million a day worth of dollars in the forex market to prevent unwanted strength in the peso. It had previously said the program could end in mid-March.

The yield on the benchmark 2020 peso-denominated bond known as TES stood at 8.349% Friday, compared with 8.290% a day earlier.